Дисертації з теми "Shear panel"
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1
Syndergaard, Parker. "Comparing Sandwich Wall Panel Shear Connector Testing Methodologies." DigitalCommons@USU, 2018. https://digitalcommons.usu.edu/etd/7002.
Повний текст джерелаАнотація:
Precast concrete sandwich wall panels (PCSWPs) have been used in the precast industry for decades due to their durability, rapid construction, and thermal efficiency. Shear connectors are used to connect the two wythes of concrete to allow composite action of the system. The use of glass fiber reinforced polymer (GFRP) connectors is a relatively recent breakthrough in PCSWP design. GFRP connectors allow full composite action to occur, while still maintaining the thermal efficiency of the system by not allowing thermal bridging to occur.
In order to design concrete sandwich panel systems to act compositely, the engineer must obtain design values from a connector manufacturer, often times making engineers uncomfortable. Shear connectors are typically proprietary and are required to first have design values often times varies by each company. This project aimed to compare existing testing methodologies in order to better inform engineers about design decisions.
This project used two methodologies of shear testing on five different types of composite action connectors. Testing was performed using single-shear and double-shear "push-off" tests. In order to gather enough statistical data to compare the testing methodologies, 22 single-shear and 48 double-shear small scale specimens were designed, fabricated, and loaded through failure at the Utah State University SMASH Lab. Testing was performed by applying loads perpendicular to the connectors and measuring the load and amount of deflection that occurred. Using the load-deflection relationships obtained, stiffness values were calculated and recorded for each test. A statistical analysis was performed based on the observed data.
This study concluded that the ultimate strength capacity and stiffness of connectors will change depending on the testing methodology used. Single-shear testing will generally provide less ultimate strength and less stiffness when compared to double-shear testing.
2
Boudreault, Félix-Antoine. "Seismic analysis of steel frame wood panel shear walls." Thesis, McGill University, 2005. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=83851.
Повний текст джерелаАнотація:
The use of steel frame/wood panel shear walls as a seismic force resisting system (SFRS) in residential and/or commercial buildings is expected to increase in the future. At the moment, in Canada, however, no specific guidelines in line with the seismic provisions of the National Building Code of Canada (NBCC) exist with which the engineer can design a building consisting of these shear walls. An extensive research program has therefore been undertaken at McGill University to develop a design method through the testing of different configurations of steel frame/wood panel shear walls loaded with monotonic and reversed cyclic protocols. A total of 16 wall configurations (109 walls) were tested over the course of the study. The CUREE Ordinary Ground Motions loading protocol was selected to represent the reversed cyclic regime because it was found to best correspond to the demand that would be imposed on a steel frame I wood panel shear wall during a typical seismic event.The analysis of test results in order to extract the principal design information was carried out using an Equivalent Energy Elastic-Plastic (EEEP) model. A ductility related (Rd) and an overstrength related (Ro) force modification factor are required for the calculation of equivalent static seismic loads following the 2005 NBCC design provisions. Values of Ro = 1.8 and Rd = 2.5 have been determined and are recommended on a preliminary basis.
The Stewart hysteretic model was found to best represent the strength and stiffness characteristics of a steel frame/wood panel shear wall component. The subsequent evaluation of building models that incorporate the Stewart model using non-linear time history dynamic analyses could then be carried out to validate the assumptions made by the EEEP method on the system ductility and the corresponding force modification factors.
3
Richardson, Benjamin Lee. "Examination of the Lateral Resistance of Cross-Laminated Timber in Panel-Panel Connections." Thesis, Virginia Tech, 2015. http://hdl.handle.net/10919/56969.
Повний текст джерелаАнотація:
Cross-Laminated Timber (CLT) combines layers of dimension lumber in alternating grain direction to form a mass timber panel that can be used to create entire wall, floor and roof elements. The viability of CLT as an element to resist lateral forces from racking has been of great interest (Dujic et al. 2004, Blass and Fellmoser 2004, and Moosbrugger et al. 2006). However, most research to date has been conducted on full-scale wall panels connected with proprietary fasteners according to European Test Methods. Little research has focused on non-proprietary connections, including nails, bolts and lag screws. The behavior of CLT full-scale wall panels is dependent upon the individual connection properties including the panel-panel connections between adjoining CLT panels within the wall.
The purpose of this research is to evaluate the behavior of three small-scale CLT connection configurations using non-proprietary fasteners. Three different connections -LVL surface spline with lag screws, half-lap joint with lag screws, and butt joint with a steel plate fastened with nails - were tested in both monotonic and cyclic tests. In all, 30 connection tests were conducted, with 15 monotonic test and 15 cyclic tests. Connection strength, stiffness, and ductility were recorded for each connection. Experimental values were compared to National Design Specification for Wood Construction, or NDS (AWC 2012) predictions for connection strength.
Nailed steel plate connections yielded much greater loads and behaved in a more ductile manner than did the lag screwed connections. The surface spline and half-lap connections often failed in a catastrophic manner usually due to splitting of the spline and fastener failure. Experimental results were generally lower than predicted by the yield models for the surface spline and steel plate connections. The half-lap connection resulted in higher experimental results than predicted. A discussion of the connection strength for materials with a non-homogeneous grain direction is also included.Master of Science
4
Chen, Chang Yi 1973. "Testing and performance of steel frame wood panel shear walls." Thesis, McGill University, 2004. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=82476.
Повний текст джерелаАнотація:
Light gauge steel frame/wood panel shear walls are more commonly being used in the residential and low-rise building markets. However in Canada, no design guide for these shear walls has been published. Furthermore, although laboratory investigations that cover the performance of light gauge steel frame/wood panel shear walls with different sheathing material have been carried out, no analytical methods have been developed to predict the in-plane stiffness and strength of light gauge steel/wood panel shear walls based on member and connection properties.This thesis has two main objectives. One is to investigate the performance characteristics of various configuration light gauge steel frame/wood panel shear walls under monotonic and reversed cyclic loading. The second is to recommend an effective analytical model, which relies on sheathing-to-framing connection test results and the mechanical properties of structural sheathing and steel frame members, to predict the resistance and deflection of shear walls subjected to lateral loads.
5
Jamison, Jared Bernard Jr. "Monotonic and Cyclic Performance of Structurally Insulated Panel Shear Walls." Thesis, Virginia Tech, 1997. http://hdl.handle.net/10919/35751.
Повний текст джерелаАнотація:
The majority of residential construction and a significant portion of light commercial and industrial construction has been, and will continue to be light-framed timber construction. In recent years, innovations have surfaced to improve upon light-framed construction. Structurally insulated panels (SIPS) are gaining popularity due to their superior energy efficiency and ease of construction. Light-framed timber construction has proven to be trustworthy in high-wind and seismic regions due to its lightweight construction and numerous redundancies. Shear walls, along with floor and roof diaphragms, resist lateral loads in a timber structure. In the past, research has focused on the static racking performance of light-framed shear walls. More recently, research has been focused on the cyclic and dynamic performance of shear walls.
To the author's knowledge, no other research is reported in the literature on the cyclic performance of SIPS shear walls. It is important to understand and quantify the monotonic and cyclic response of shear walls. In this study, twenty-three full-scale shear walls were tested under monotonic loading and sequential phased displacement cyclic loading. Four different wall configurations were examined. Monotonic and cyclic performance of the shear walls and monotonic and cyclic testing procedures are compared. Response of SIPS shear walls is also compared to the response of light-framed shear walls based on capacity, stiffness, ductility, energy dissipation, damping characteristics, and overall behavior. Results of this study will provide useful information regarding the performance of SIPS shear walls and similar systems subjected to static, cyclic, and dynamic lateral loads.Master of Science
6
Hikita, Katherine. "Combined gravity and lateral loading of light gauge steel framewood panel shear walls." Thesis, McGill University, 2006. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=99767.
Повний текст джерелаАнотація:
Methods for the design of steel frame/wood panel shear walls used as a seismic force resisting system have been developed. These methods, which can be used in conjunction with the 2005 NBCC, were based on the results of shear wall tests carried out using lateral loads alone. The research program was extended to determine the influence of gravity loads on the lateral performance of the shear wall. An initial series of stud column tests was completed to determine an appropriate predication method for the axial capacity of the principal vertical load carrying members. Recommendations for appropriate effective length factors and buckling lengths were derived from the results of 40 tests. A subsequent series of five single-storey shear wall configurations were designed using capacity based methods. These shear walls were tested under monotonic and cyclic lateral loading, where two of three shear walls were also subjected to a constant gravity load. In total, 32 steel frame/wood panel shear walls composed of 1.09--1.37 mm thick steel studs sheathed with DFP, CSP or OSB panels were tested and analyzed. The equivalent energy elastic-plastic analysis approach was used to determine design values for stiffness, strength, ductility and overstrength. The data from this most recent series of tests indicates that the additional gravity loads do not have a detrimental influence on the lateral behaviour of a steel frame/wood panel shear wall if the chord studs are designed to carry the combined lateral and gravity forces following a capacity based approach. A resistance factor of 0.7 was found to be in agreement with previous tests that did not include gravity loads. The calculated seismic force modification factors also agreed with the previous test results, which suggest that Rd = 2.5 and Ro = 1.7.
7
Branston, Aaron E. "Development of a design methodology for steel frame wood panel shear walls." Thesis, McGill University, 2004. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=81531.
Повний текст джерелаАнотація:
This thesis provides details on the 109 specimen main testing program as well as a summary of past wood frame and steel frame shear wall research. An extensive review of existing data interpretation methodologies is presented. The equivalent energy elastic-plastic (EEEP) technique is chosen as most suitable for the wall systems under study to deduce key design parameters including the yield wall resistance, elastic stiffness, and system ductility. It is recommended that the EEEP methodology be implemented for all future steel frame/wood panel shear wall data interpretation. The calibration of a resistance factor for use with the limit states design philosophy consistent with the upcoming draft version of the 2005 National Building Code of Canada (NBCC) is also presented.It was found that a resistance factor (phi) of 0.7 provided sufficient reliability and a reasonable factor of safety under the NBCC wind loading case. Final nominal strength and unit elastic stiffness values for use in design are presented in tabular format according to given perimeter fastener schedules. Finally, recommendations for future research and testing are outlined. (Abstract shortened by UMI.)
8
Sullivan, Sean Robert. "Construction and Behavior of Precast Bridge Deck Panel Systems." Diss., Virginia Tech, 2007. http://hdl.handle.net/10919/27479.
Повний текст джерелаАнотація:
A bridge with precast bridge deck panels was built at the Virginia Tech Structures Laboratory to examine constructability issues, creep and shrinkage behavior, and strength and fatigue performance of transverse joints, different types of shear connectors, and different shear pocket spacings. The bridge consisted of two AASHTO type II girders, 40 ft long and simply supported, and five precast bridge deck panels. Two of the transverse joints were epoxied male-female joints and the other two transverse joints were grouted female-female joints. Two different pocket spacings were studied: 4 ft pocket spacing and 2 ft pocket spacing. Two different shear connector types were studied: hooked reinforcing bars and a new shear stud detail that can be used with concrete girders.
The construction process was well documented. The change in strain in the girders and deck was examined and compared to a finite element model to examine the effects of differential creep and shrinkage. After the finite element model verification study, the model was used to predict the long term stresses in the deck and determine if the initial level of post-tensioning was adequate to keep the transverse joints in compression throughout the estimated service life of the bridge. Cyclic loading tests and shear and flexural strength tests were performed to examine performance of the different pocket spacings, shear connector types and transverse joint configurations. A finite element study examined the accuracy of the AASHTO LRFD shear friction equation for the design of the horizontal shear connectors.
The initial level of post-tensioning in the bridge was adequate to keep the transverse joints in compression throughout the service life of the bridge. Both types of pocket spacings and shear connectors performed exceptionally well. The AASHTO LRFD shear friction equation was shown to be applicable to deck panel systems and was conservative for determining the number of shear connectors required in each pocket. A recommended design and detailing procedure was provided for the shear connectors and shear pockets.Ph. D.
9
Dewaidi, Mohaned Ali. "Design Method for Cold-Formed Steel Shear Wall Sheathed with Polymer Composite Panel." Thesis, University of North Texas, 2020. https://digital.library.unt.edu/ark:/67531/metadc1707373/.
Повний текст джерелаАнотація:
In order to predict the strength of shear wall with cold-formed steel framing members, analytical models were reviewed. Multiple analytical models were studied, as well as twenty-one connection tests were performed. The connection tests consist of 50-ksi cold-formed steel framing track, different fastening configurations, and different sheathing thicknesses (1/8" and 1/2"). No.12 screw resulted in the highest peak load of all fastening configurations, while the rivet connection had the lowest peak load. In addition, failure modes were observed after conducting the connection tests including shear in fastening, screw pullout, and bearing in the sheathing. However, only the rivet and No.10 screw fastening configurations were used in the prediction analysis of the shear wall by the elastic model. Six shear wall tests were conducted on both panels (1/2"and 1/8" thickness). After doing the comparison between the experimental and the elastic model, the percentage difference for the 1/8" and the 1/2" polymer composite panels (3''along the edge and 6''along the chord stud), was very small. It was 6.2% for the 1/8" and 2.96% for the 1/2" panels. This means the analytical model can predict the shear wall peak load. However, the percentage difference was slightly higher being 7.4% for the 1/2" polymer composite panels with 6" along the perimeter with the 12" at the chord stud. After comparing the experimental values to the predicted value of shear walls, it was concluded that this model is the most appropriate analytical method for predicting the shear wall capacity framed with cold-formed steel sheathed with polymer composite panels. Many of these configurations were used in a prototype shelter that was constructed and built at the structural testing laboratory at the University of North Texas.
10
Ashkanalam, Aida. "Design Method of Cold-Formed Steel Framed Shear Wall Sheathed by Structural Concrete Panel." Thesis, University of North Texas, 2019. https://digital.library.unt.edu/ark:/67531/metadc1609092/.
Повний текст джерелаАнотація:
The objective of this research is developing a new method of design for cold-formed steel framed shear wall sheathed by ¾" thick USG structural panel concrete subfloor using a predictive analytical model and comparing the results obtained from the model with those achieved from real testing to verify the analytical model and predicted lateral load-carrying capacity resulted from that. Moreover, investigating the impact of various screw spacings on shear wall design parameter such as ultimate strength, yield strength, elastic stiffness, ductility ratio and amount of energy dissipation is another purpose of this research.
11
Woerheide, Andrew James. "Structural Performance of Longitudinally Post-Tensioned Precast Deck Panel Bridges." Thesis, Virginia Tech, 2012. http://hdl.handle.net/10919/34126.
Повний текст джерелаАнотація:
As the aging bridges and infrastructure within the US continue to deteriorate, traffic delays due to
construction will become more and more common. One method that can reduce delays due to bridge
construction is to use precast deck panels. Precast deck panels can significantly reduce the overall
length of the construction project. The panels can be manufactured ahead of time, and with higher
quality control than is possible in the field. One of the reasons precast deck panels are not widely
accepted is because of a lack of research concerning the required post-tensioning force, shear stud
pocket placement, and proper joint design.
In a recent dissertation (Swenty 2009) numerous recommendations were made for joint design, shear
stud pocket design, and post-tensioning force for full-depth precast deck panel bridges. Design
drawings were included for the replacement of a bridge located in Scott County, Virginia. The research
in this report focuses on the short-term and long-term testing of this bridge. The short-term testing
involved performing a live load test in which two trucks of known weight and dimensions were
positioned on the bridge in order to maximize the negative moment at the joints over the piers and
document strains and deflections at a number of other critical locations. The long-term testing involved
monitoring the strains within the deck and on one of the six girders for a number of months in order to
document the changes in strain due to creep and shrinkage. The results of these tests were compared
to 2D beam-line models and to the parametric study results of Bowersâ research on prestress loss within
full-depth precast deck panel bridges. It was determined that the bridge was acting compositely and
that the post-tensioning force was sufficient in keeping the joints in compression during testing.Master of Science
12
Blais, Caroline 1980. "Testing and analysis of light gauge steel frame 9 mm OSB wood panel shear walls." Thesis, McGill University, 2006. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=98945.
Повний текст джерелаАнотація:
The use of light steel gauge framed walls in the residential and commercial sector is increasing in popularity. However, our knowledge of the performance and the behaviour of structures using such walls when subjected to lateral wind and seismic loads is limited. At present, no design method for light gauge steel shear walls is contained in Canadian codes or standards. For this reason a research project on steel frame/wood panel shear walls was undertaken.A comprehensive database of monotonic and reversed cyclic tests on steel frame/wood panel shear walls is needed to obtain different wall parameters for use in design. For this particular project 1220 x 2440 mm walls (3 wall configurations for a total of 18 specimens) composed of 1.09 mm thick 230 MPa grade steel and 9.0 mm thick OSB were tested; where the screw spacing along the perimeter of the wall was varied (75, 100 & 152 mm). The equivalent energy elastic-plastic (EEEP) analysis approach was employed to derive design values from the test results; such as stiffness, strength and a resistance factor for use with the 2005 NBCC, as well as ductility and overstrength modification factors. The resistance factor, o = 0.7, determined by Branston was confirmed. Ductility related, Rd = 2.5, and overstrength related, R0 = 1.8, seismic force modification factors are recommended for use with shear wall design values that are based on the EEEP analysis approach.
Furthermore, the test data were used to create and calibrate hysteretic models, with the Stewart element, which later were used in non-linear time history dynamic analyses. The Ruaumoko software was made use of for the modeling of two representative buildings with ten earthquake records for the Vancouver BC region. The shear wall system of a typical two-storey house and a three-storey commercial building was first designed for lateral loads and then modeled. The resulting shear deformations (rotations) obtained from the analyses were compared with the limiting parameters measured during the physical shear wall tests. It was found that the scaled ground motions caused a shear demand that did not exceed the test based deformation limits.
13
Odiam, David Michael. "Comparison of Slice Shear Force with Warner Bratzler Shear Force as Predictors of Consumer Panel Palatability Measures in Non-enhanced and Enhanced Pork Loin Chops." The Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=osu1236602515.
Повний текст джерела
14
Lim, Albert Kee Wah. "Non-linear response of reinforced concrete coupling slab with drop panel in earthquake-resisting shear wall structures." Thesis, McGill University, 1989. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=55618.
Повний текст джерела
15
Naji, Behnam. "Flexural Analysis and Composite Behavior of Precast Concrete Sandwich Panel." University of Dayton / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1355331734.
Повний текст джерела
16
Gjata, Marjus. "Seismic Behavior of Dowel Type Precast Panel-Foundation Connection." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2017.
Знайти повний текст джерелаАнотація:
Precast concrete panels are a popular construction technique due to their increased construction speed, low cost and the ability to use the precast concrete elements for structural walls to provide high strength and stiffness when used for structural purposes. Slender precast concrete wall panels are a common construction method for single storey warehouse type buildings.
Following the Canterbury earthquake sequence Christchurch from 2010 – 2014, damage was observed in precast concrete wall buildings that resulted in out-of-plane collapse of wall panels. . This project seeks to investigate the behaviour of precast reinforced concrete walls designed for limited ductility under gravity and quasi-static in-plane loading. The main point of interest in this thesis research is to understand the seismic behaviour of the connection as well as the out-of-plane stability of slender panels.
To investigate the behaviour of this panel and connection type, three slender precast concrete walls, representing full scale panel geometry were subjected to quasi-static cyclic loading. Two common panel to foundation connection types were studied: 1) threaded inserts and 2) traditional starter bars as well as one alternative connection which was developed as a means to improve the out-of-plane response and understand the impact of this design choice on the in-plane behavior of the wall.
For all the three units, the dowel connection performed well and the thin wall failed under flexural failure due to loss of strength cause by fracturing of longitudinal rebars after being buckled under the effects of lateral cyclic loading. Significant horizontal cracking occurred on each of the tests at dowel level except unit threaded insert with 50mm cover behind the head of the insert (TI12-C50-IP) which suffered a secondary horizontal crack at 500mm above the main crack and a diagonal crack at the center of the wall. Moreover, this unit was able to undergo more deformation due to a secondary crack.
17
Huerta, Sanchez Diana Lorena. "Identifying beef muscles and processing treatments suitable for use in fajita application." [College Station, Tex. : Texas A&M University, 2006. http://hdl.handle.net/1969.1/ETD-TAMU-1721.
Повний текст джерела
18
Gualtero, Ivan A. "Deterioration Process and Deck Failure Mechanism of Florida’s Precast Deck Panel Bridges." Scholar Commons, 2004. https://scholarcommons.usf.edu/etd/1058.
Повний текст джерелаАнотація:
During the late 70's and early 80's, several precast deck panel bridges were constructed in Florida. These utilize prestressed precast panels as stay-in-place forms and are designed to act compositely with a cast-in-place deck which is poured subsequently. Such bridges offer advantages of quicker construction and lower costs. However, several such bridges built in Florida developed extensive cracking and spalling. Following localized failures, the Florida Department of Transportation has decided to replace all 127 precast panel deck bridges in Districts 1 and 7. Since deck replacement is contingent on funding, it is necessary to develop a rational procedure to decide the order in which they are replaced. This requires a better understanding of the deterioration process and failure mechanism in such bridge decks. The methodology used in this study was to first analyze in detail 5 cases of sudden localized deck failures to identify the causes of the failures and any common factors in the failed bridges. Also, forensic studies were conducted on eight bridges scheduled for deck replacements during 2003 and 2004. In these studies it was possible to investigate in detail the condition of the deck at different stages of deterioration. Based on the information collected, a deck failure model was developed.
19
Yuksel, Bahadir S. "Experimental Investigation Of The Seismic Behavior Of Panel Buildings." Phd thesis, METU, 2003. http://etd.lib.metu.edu.tr/upload/2/1070309/index.pdf.
Повний текст джерелаАнотація:
Shear-wall dominant multi-story reinforced concrete structures, constructed by using a special tunnel form technique are commonly built in countries facing a substantial seismic risk, such as Chile, Japan, Italy and Turkey. In 1999, two severe urban earthquakes struck Kocaeli and Düzce provinces in Turkey with magnitudes (Mw) 7.4 and 7.1, respectively. These catastrophes caused substantial structural damage, casualties and loss of lives. In the aftermath of these destructive earthquakes, neither demolished nor damaged shear-wall dominant buildings constructed by tunnel form techniques were reported. In spite of their high resistance to earthquake excitations, current seismic code provisions including the Uniform Building Code and the Turkish Seismic Code present limited information for their design criteria. This study presents experimental investigation of the panel unit having H-geometry. To investigate the seismic behavior of panel buildings, two prototype test specimens which have H wall design were tested at the Structural Mechanics Laboratory at METU. The experimental work involves the testing of two four-story, 1/5-scale reinforced concrete panel form building test specimens under lateral reversed loading, simulating the seismic forces and free vibration tests. Free vibration tests before and after cracking were done to assess the differences between the dynamic properties of uncracked and cracked test specimens. A moment-curvature program named Waller2002 for shear walls is developed to include the effects of steel strain hardening, confinement of concrete and tension strength of concrete. The moment-curvature relationships of panel form test specimens showed that walls with very low longitudinal steel ratios exhibit a brittle flexural failure with very little energy absorption. Shear walls of panel form test specimens have a reinforcement ratio of 0.0015 in the longitudinal and vertical directions. Under gradually increasing reversed lateral loading, the test specimens reached ultimate strength, as soon as the concrete cracked, followed by yielding and then rupturing of the longitudinal steel. The displacement ductility of the panel form test specimens was found to be very low. Thus, the occurrence of rupture of the longitudinal steel, as also observed in analytical studies, has been experimentally verified. Strength, stiffness, energy dissipation and story drifts of the test specimens were examined by evaluating the test results.
20
Roberts, Kayde Steven. "Performance of Transverse Post-Tensioned Joints Subjected to Negative Bending and Shear Stresses on Full Scale, Full Depth, Precast Concrete Bridge Deck System." DigitalCommons@USU, 2011. https://digitalcommons.usu.edu/etd/934.
Повний текст джерелаАнотація:
Accelerated bridge construction has quickly become the preferred method for the Utah Department of Transportation (UDOT) as well as many other DOT’s across the United States. This type of construction requires the use of full depth precast panels for the construction of the bridge deck. The segmented deck panels produce transverse joints between panels and have come to be known as the weakest portion of the deck. Cracking often occurs at these joints and is reflected through the deck overlay where water accesses and begins corrosion of the reinforcement and superstructure below. For this reason post-tensioning of the deck panels is becoming a regular practice to ensure that the deck behaves more monolithically, limiting cracking. The current post-tensioning used by UDOT inhibits future replacement of single deck panels and requires that all panels be replaced once one panel is deemed defective. The new curved bolt connection provides the necessary compressive stresses across the transverse joints but makes future replacement of a single deck panel possible without replacing the entire bridge deck. To better understand the behavior of the new curved bolt connection under loadings, laboratory testing was undertaken on both the curved bolt and the current post-tensioning used by UDOT. The testing specimens included full-scale, full-depth, precast panels that were connected using both system. The testing induced typical stresses on the panels and connections, subjecting them to negative bending and shear. The overall performance of the curved bolt proved satisfactory. The moment capacity of both connections surpassed all theoretical calculations. The yield and plastic moments were 17% and 16% lower, respectively, than the UDOT post-tension system while at those moments deflection was relatively the same. Due to the anchorage location of the curved bolts, the reinforcement around the transverse joint received up to 5 times the strain of that of the post-tension connections. Although both systems performed well when subjected to shear forces and as compared to the theoretical capacities, the post-tension connection greatly surpassed the curved bolt in shear capacity.
21
Susoy, Melih. "Seismic Strengthening Of Masonry Infilled Reinforced Concrete Frames With Precast Concrete Panels." Master's thesis, METU, 2004. http://etd.lib.metu.edu.tr/upload/12605563/index.pdf.
Повний текст джерелаАнотація:
Over 90% of the land area of Turkey lies over one of the most active seismic zones in the world. Hazardous earthquakes frequently occur and cause heavy damage to the economy of the country as well as human lives. Unfortunately, the majority of buildings in Turkey do not have enough seismic resistance capacity. The most commonly observed problems are faulty system configuration, insufficient lateral stiffness, improper detailing, poor material quality and mistakes during construction. Strengthening of R/C framed structures by using cast-in-place R/C infills leads to a huge construction work and is time consuming. On the other hand, using prefabricated panel infills can be preferred as a more feasible, rapid and easy technique during which the structure can remain operational.
The aim of this experimental study is to observe the seismic behavior of R/C frames strengthened by precast concrete panel infills by testing different types of panel and connection designs in eight single-story single-bay reinforced concrete
frame specimens.
22
David, Carlos Rodrigo Pinheiro. "Simulação numérica de painéis de concreto armado submetidos ao corte puro." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2010. http://hdl.handle.net/10183/21421.
Повний текст джерелаАнотація:
A análise de painéis de concreto armado submetidos a corte puro é um tópico que tem recebido atenção de pesquisadores ao longo dos anos. Isto se deve, principalmente, à dificuldade encontrada na aplicação do carregamento e das condições de vinculação sobre a estrutura. Esta dificuldade é constatada tanto experimentalmente como na análise numérica. O objetivo deste trabalho é apresentar um modelo numérico para simular o comportamento de painéis de concreto simples e de concreto armado submetidos ao corte. Na análise computacional via Elementos Finitos, será utilizado um modelo de fissura incorporada que considera a contribuição da armadura no equilíbrio interno de forças do elemento. Estes modelos se baseiam no conceito de descontinuidades incorporadas dentro de elementos finitos padrão. O modelo incorporado implementado é uma continuação dos trabalhos desenvolvidos por d’Avila (2003) e Brisotto (2006), baseados no modelo de Dvorkin, Cuitiño e Gioia (1990). O modelo de transferência de tensão por aderência de Russo, Zingone e Romano (1990) foi usado por d’Avila para incluir a contribuição da armadura no equilíbrio interno de forças do elemento. Para representar as barras de aço da armadura, é utilizado o modelo incorporado desenvolvido por Elwi e Hrudey (1989) que permite a disposição arbitrária das barras no interior dos elementos de concreto. Os resultados dos ensaios numéricos de painéis de concreto armado submetidos ao corte puro com diferentes taxas de armadura são comparados com os resultados experimentais apresentados por Vecchio (1981). São incluídos dois diferentes modelos de efeito de pino (resistência ao corte das barras da armadura), analisando-se a influência dos mesmos no comportamento dos painéis ensaiados. O efeito do engrenamento dos agregados na fissura também foi estudado. Vários painéis com diferentes formas de ruptura experimental foram simulados, obtendo-se respostas muito boas para a maioria deles. Comparações da resposta tensão tangencial x distorção com e sem efeito de pino foram feitas, verificando-se a grande importância deste efeito na resposta global.The analysis of reinforced concrete panels submitted to in-plane shear has received the attention of researchers along the years. It is mainly due to the difficulty to simulate the application of the external loads and the structural boundary conditions. The purpose of this work is to present a numerical model to represent reinforced concrete panels submitted to inplane shear. In the computational analysis via Finite Elements, an embedded crack model that considers the inclusion of the reinforcement contribution in the internal force equilibrium of the element is presented. This type of model is based in discontinuities embedded into standard finite elements. The implemented formulation uses the model presented by Dvorkin, Cuitiño and Gioia (1990), which does not have the reinforcement contribution in the element internal equilibrium. The adherence stress transfer model of Russo, Zingone and Romano (1990) is used to include this reinforcement contribution. An embedded model was employed to represent the reinforcement bars, allowing that they can be placed in an independent position and shape in the FEM elements. The numerical results are compared with Vecchio’s work. Also are included two different dowel action models (transversal shear resistance of the bars) and is studied their influence in the panels’ behavior. Panels with different experimental rupture modes were simulated with good responses in the most cases. Comparisons of shear stress x shear strain curve with and without dowel action are performed, showing the importance of this effect on the global response.
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Decker, Brandon T. "In-Plane Lateral Load Capacities of Vertically Oriented Interlocking Timber Panels." BYU ScholarsArchive, 2014. https://scholarsarchive.byu.edu/etd/5304.
Повний текст джерелаАнотація:
The Vertically Oriented Interlocking Timber (VOIT) panel is a new solid wood panel similar to Interlocking Cross Laminated Timber (ICLT) and the more commonly known Cross Laminated Timber (CLT). Like ICLT, VOIT panels use timber connections instead of the adhesives or metal fasteners common to CLT. The difference of VOIT is the orientation of the layers. Where CLT and ICLT panels alternate the orientation of each layer, VOIT panels orient all the layers in the same direction. The vertically oriented layers are then attached to one another by smaller horizontal dovetail members.Two types of VOIT panels were provided to be tested for in-plane lateral loading. Type I had three rows of horizontal dovetail members connecting the layers and Type II had four rows of dovetail members as well as two diagonal members to provide stiffness. Two panels of each type were provided, measuring 8 ft. wide, 8 ft. tall, and 13.75 in. thick. Each panel was disassembled after monotonic lateral in-plane loading to determine possible failure modes. Testing results suggest the VOIT panels to be comparable in shear strength to other wood shear walls, including light frame, CLT, and ICLT walls. A two-part analytical model was created to determine the deflection of the wall when loaded as well as the shear strength of the wall. The model predicted deflection and wall strength reasonably well. Due to the small sample size, additional testing is necessary to confirm the results of the Type I and Type II VOIT panels. Additional testing with more variations of the panel and member geometries is also needed to validate the scope of the model.
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Wallenfelsz, Joseph A. "Horizontal Shear Transfer for Full-Depth Precast Concrete Bridge Deck Panels." Thesis, Virginia Tech, 2006. http://hdl.handle.net/10919/31943.
Повний текст джерелаАнотація:
Full-depth precast deck panels are a promising alternative to the conventional cast-in-place concrete deck. They afford reduced construction time and fewer burdens on the motoring public. In order to provide designers guidance on the design of full-depth precast slab systems with their full composite strength, the horizontal shear resistance provided at the slab-to-beam interface must be quantified through further investigation. Currently, all design equations, both in the AASHTO Specifications and the ACI code, are based upon research for cast-in-place slabs. The introduction of a grouted interface between the slab and beam can result in different shear resistances than those predicted by current equations.
A total of 29 push off tests were performed to quantify peak and post-peak shear stresses at the failure interface. The different series of tests investigated the surface treatment of the bottom of the slab, the type and amount of shear connector and a viable alternative pocket detail.
Based on the research performed changes to the principles of the shear friction theory as presented in the AASHTO LRFD specifications are proposed. The proposal is to break the current equation into two equation that separate coulomb friction and cohesion. Along with these changes, values for the coefficient of friction and cohesion for the precast deck panel system are proposed.Master of Science
25
Williams, Ashley Philip. "Post-buckling of truss-lattice shear panels." Thesis, University of Bath, 2007. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.488877.
Повний текст джерела
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Menkulasi, Fatmir. "Horizontal Shear Connectors for Precast Prestressed Bridge Decks." Thesis, Virginia Tech, 2002. http://hdl.handle.net/10919/34713.
Повний текст джерелаАнотація:
The full-width, full-depth precast panel system is very convenient for rehabilitation of deteriorated decks as well as for new bridge construction. The horizontal shear strength at the interface between the two interconnected elements is of primary importance in order to provide composite action. The strength of the bond between the two precast members should be high enough to prevent any progressive slip from taking place. Flexural strength, shear strength and deflection characteristics all depend on the satisfactory performance of the interface to provide composite action. However, the case when both of the interconnected elements are precast members bonded by means of grout, is not currently addressed by ACI or AASHTO. This is the main impetus for this project.
A total of 36 push-off tests were performed to develop a method for quantifying horizontal shear strength and to recommend the best practice for the system. Test parameters included different haunch heights, different grout types, different amount and different type of shear connectors. Two equations, for uncracked and cracked concrete interfaces, are proposed to be used in horizontal shear design when the precast panels are used.
Predictive equations are compared with available methods for the horizontal shear strength of the precast panel system. Conclusions and recommendations for the optimum system are made.Master of Science
27
Schumacher, Ann. "Connection of infill panels in steel plate shear walls." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/mq21206.pdf.
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Cafolla, Gerard James. "Hydroelastic instabilities of compliant panels." Thesis, University of Warwick, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.323370.
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Insel, Emre. "Shear testing of concrete sandwich panels with carbon fiber grid reinforcement." Laramie, Wyo. : University of Wyoming, 2007. http://proquest.umi.com/pqdweb?did=1313919671&sid=1&Fmt=2&clientId=18949&RQT=309&VName=PQD.
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30
Davidson, Paul Cameron. "Design of plate panels under biaxial compression, shear and lateral pressure." Thesis, Imperial College London, 1990. http://hdl.handle.net/10044/1/46272.
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Larose, Kent Evan. "Performance of shear stud clusters for precast concrete bridge deck panels." Thesis, University of British Columbia, 2006. http://hdl.handle.net/2429/31661.
Повний текст джерелаАнотація:
The current edition of the Canadian Highway Bridge Design Code (CHBDC), CAN/CSA-S6-00
provides limited guidance for the design of composite bridges with precast concrete deck panels
and steel girders. The shear connection is critical in determining the overall performance of the
composite superstructure and is commonly achieved with a grout blockout in a precast concrete
deck panel, which accepts a cluster of tightly spaced steel shear studs. No specific equations are
found in the CHBDC for the design of shear studs used in this system. Furthermore, the current
longitudinal spacing limitation of 600 mm for shear studs in the CHBDC is not conducive to the
construction of precast concrete decks where an increased spacing of the stud cluster is desirable.
An experimental testing regime was completed using push-test specimens constructed with
precast concrete panels connected to steel flanges with steel studs within a circular grout pocket.
Specimens were tested to failure to determine the ultimate capacity of a stud cluster and to
investigate the reduction in ultimate strength after exposure to a number of loading cycles.
A 36 m simple span composite superstructure was designed to the CHBDC. A parametric study
was conducted on the spacing of stud clusters to investigate the serviceability limit state of the
composite superstructure using data captured from the push test specimens.
Experiments show that clustered shear studs embedded in high strength grout for construction
using precast deck panels meet CHBDC strength requirements and that exceeding the code
maximum stud spacing of 600 mm by a factor of two will not result in excessive displacements.Applied Science, Faculty of
Civil Engineering, Department of
Graduate
32
Vessby, Johan. "Shear walls for multi-storey timber buildings." Licentiate thesis, Växjö University, School of Technology and Design, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:vxu:diva-2420.
Повний текст джерелаАнотація:
Wind loads acting on wooden building structures need to be dealt with adequately in order to ensure that neither the serviceability limit state nor the ultimate limit state is exceeded. For the structural designer of tall buildings, avoiding the possibly serious consequences of heavy wind loading while taking account at the same time of the effects of gravitation can be a real challenge. Wind loads are usually no major problem for low buildings, such as one- to two-storey timber structures involving ordinary walls made by nailing or screwing sheets of various types to the frame, but when taller structures are designed and built, serious problems may arise.
Since wind speed and thus wind pressure increases with height above the ground and the shear forces transmitted by the walls increase accordingly, storey by storey, considerable efforts can be needed to handle the strong horizontal shear forces that are exerted on the bottom floor in particular. The strong uplift forces that can develop on the wind side of a structure are yet another matter that can be critical. Accordingly, a structure needs to be anchored to the substrate or to the ground by connections that are properly designed. Since the calculated uplift forces depend very much upon the models employed, the choice of models and simplifications in the analysis that are undertaken also need to be considered carefully.
The present licentiate thesis addresses questions of how wind loads acting on multi-storey timber buildings can be best dealt with and calculated for in the structural design of such buildings. The conventional use of sheathing either nailed or screwed to a timber framework is considered, together with other methods of stabilizing timber structures. Alternative ways of using solid timber elements for stabilization are also of special interest.
The finite element method was employed in simulating the structural behaviour of stabilizing units. A study was carried out of walls in which sheathing was nailed onto a timber frame. Different structural levels were involved, extending from modelling the performance of a single fastener and of the connection of the sheathing to frame, to the use of models of this sort for studying the overall structural behaviour of wall elements that possess a stabilizing function. The results of models used for simulating different load cases for walls agreed reasonably well with experimental test results. The structural properties of the fasteners binding the sheathing to the frame, as well as of the connections between the members of the frame were shown to have a strong effect on the simulated behaviour of shear wall units.
Regarding solid wall panels, it was concluded that walls with a high level of both stiffness and strength can be produced by use of such panels, and also that the connections between the solid wall panels can be designed in such a way that the shear forces involved are effectively transmitted from one panel to the next.
33
Broussard, Dylan W. "Cyclic Behavior of Small Scale Shear Panels Containing Fiber Reinforced Rubber Concrete." Thesis, University of Louisiana at Lafayette, 2016. http://pqdtopen.proquest.com/#viewpdf?dispub=10002460.
Повний текст джерелаАнотація:
Shear beams and shear walls were constructed using varying amounts of steel fibers and rubber to determine the effect of these constituents on concrete when subject to shear loads and reversed cyclic loadings. 22 concrete beams were tested using mixes with differing amounts of fibers and rubber. The beams were designed to fail in shear by applying a single downward point load at midspan using a MTS Universal Testing Machine. Using the recorded load and displacement data the behavior of each beam and the shear strength contribution for each mix were determined. For all mixes that included fibers and/or rubber the shear strengths increased 12% to 56% in comparison to the plain concrete mixes. Four concrete walls were also tested using four of the 22 beam mixes. The four selected mixes were chosen based on the comparable compressive strengths and mix constituents. The walls were designed to fail in shear by applying a lateral load to a top block cast on top of the shear wall. The walls were tested on a modular strong-block test system within a rigid steel frame so that the load could be applied by a hydraulic actuator. During testing, the displacement at 10 selected locations, the loads placed on the walls at each displacement, and the behavior were recorded and analyzed. The walls containing rubber experienced lower strengths, a brittle failure with severe spalling and damage, and dissipated a low amount of energy. The walls containing fibers exhibited strain hardening characteristics leading to a ductile failure mode, higher strengths, and little web damage. Using the findings from this study, it can be concluded that both fibers and rubber can be used to increase shear strength but only fibers were found to be a viable option for application in walls subject to reverse cyclic loadings.
34
Chandiramani, Naresh K. "Nonlinear flutter of composite shear-deformable panels in a high-supersonic flow." Diss., Virginia Tech, 1993. http://hdl.handle.net/10919/40149.
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Bredel, Daniel. "Performance Capabilities of Light-Frame Shear Walls Sheathed With Long OSB Panels." Thesis, Virginia Tech, 2003. http://hdl.handle.net/10919/32849.
Повний текст джерелаАнотація:
In this investigation, thirty-six shear walls measuring 8 feet (2.4 m) in width and possessing heights of 8, 9 and 10 feet (2.4, 2.7 and 3.0 m) were subjected to the reversed, cyclic loading schedule of the standard CUREE protocol in order to determine the performance capabilities of shear walls greater than 8 feet (2.4 m) in height sheathed with long panels. Of the thirty-six walls, a total of twelve walls measuring 9 and 10 feet (2.7 and 3.0 m) in height were sheathed with 4 x 8 feet (1.2 x 2.4 m) panels which required additional blocking members between the studs of the frame. Values obtained from the tests performed on these walls provided a direct comparison to those obtained from the walls of equal height, but sheathed with a long panel capable of spanning the entire height of the wall. The capabilities of long panels were investigated when used as the sheathing elements of shear walls with and without a mechanical hold-down device attached to the base of the end stud. An advantage of the long panel was investigated in which it was extended past the bottom plate and down onto the band joist to determine if significant resistance to the uplift present in walls without mechanical hold-down devices could be provided. Also, the effects of orienting the fibers of a 4 x 9 feet (1.2 x 2.7 m) panel in the alternate direction were examined.
Average values of the parameters produced by walls sheathed with long panels either matched or exceeded those of its counterpart sheathed with 4 x 8 feet (1.2 x 2.4 m) panels in all configurations except the 10 feet (3.0 m) tall wall without hold-down devices. In fact, 4 x 9 feet (1.2 x 2.7 m) panels increased the performance of 9 feet (2.7 m) tall walls equipped with hold-down restraint significantly.
Extending the long panels past the bottom plate and down onto the band joist improved the performance of both 8 and 9 feet (2.4 and 2.7 m) tall prescriptive shear walls significantly.
Walls sheathed with panels made of fibers oriented in the alternate direction performed identically to those sheathed with panels of typical fiber orientation until the point of peak load. Once peak load was reached, walls sheathed with panels of alternate oriented fibers failed in a more sudden and brittle manner.Master of Science
36
Pozo, Fray. "On Thermal Bowing of Concrete Sandwich Wall Panels with Flexible Shear Connectors." DigitalCommons@USU, 2018. https://digitalcommons.usu.edu/etd/7133.
Повний текст джерелаАнотація:
Thermal bowing, often referred as bulging or out-of-plane wall deflection, is a common issue on sandwich panel walls caused by a temperature differential between a building interior temperature and the environment. The stresses caused by temperature changes in concrete members are widely known in the practice of bridge design, but not on sandwich wall panels. For sandwich wall panel applications, it is common to have non-composite panels when the designer expects a high temperature gradient, what yields a less economical design, but reduces the bowing.
This project aimed to validate current assumptions regarding the heat flow in sandwich wall panels and to perform a parametric study of panels subject to thermal loads, varying the concrete layer thickness, panel length, type of shear connector and separation using a commercial finite element analysis software. This study concluded that current design practices either underestimate, in the case of multiplying the classical mechanics values by the reported degree of composite behavior, or overestimate the real value of bowing, by using classical mechanics. A method for determining the percentage of composite action and compute bowing was developed and recommendations addressing the importance of this type of loading were given.
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Young, Richard Douglas. "Prebuckling and postbuckling behavior of stiffened composite panels with axial-shear stiffness coupling." Diss., This resource online, 1996. http://scholar.lib.vt.edu/theses/available/etd-06062008-144734/.
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Vessby, Johan. "Analysis of shear wallsfor multi-storey timber buildings." Doctoral thesis, Linnéuniversitetet, Institutionen för teknik, TEK, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-11489.
Повний текст джерелаАнотація:
This doctoral thesis addresses questions of how wind loads acting on multistoreytimber buildings can be dealt with by structural design of such buildings.The conventional use of sheathing either nailed or screwed to a timberframework is considered, together with other stabilizing structures such ascross-laminated timber panels.The finite element method was employed in simulating the structuralbehaviour of stabilizing wall units. A series of studies was carried out of walls inwhich the sheathing was nailed to a timber frame. Different structural levelswere studied starting with modelling the performance of single sheathing-toframingconnections, to the use of models for studying the overall structuralbehaviour of walls. The results of calculations using models for simulation ofwalls subjected to different loading agree reasonably well with experimentalresults. The structural properties of the connections between the sheathing andthe frame, as well as of the connections between the members of the frame,were shown to have a substantial effect on the simulated behaviour of shearwall units. Both these types of connections were studied and described inappended papers.Regarding cross-laminated timber wall panels, it was concluded that walls witha high level of both stiffness and strength can be produced by the use of suchpanels, and also that the connections between the solid wall panels can bedesigned in such a way that the shear forces involved are transmitted from onepanel to the next in an efficient manner.Other topics in the thesis include the properties of connections between shearwalls and the rest of the building. Typically high tension forces occur at specificpoints in a timber structure. These forces need to be transmitted downwards inthe structure, ultimately connecting them to the substrate. A lap-joint that maybe used for this purpose has been studied using generalized Volkersen theory.Finally the maximum capacity of a conventional rail to substrate connection hasbeen examined using linear and nonlinear fracture mechanics.
39
Bono, Matthew P. (Matthew Paul). "Tilt-up concrete panels : an investigation of flexural stresses and punching shear during lifting." Thesis, Massachusetts Institute of Technology, 2011. http://hdl.handle.net/1721.1/66823.
Повний текст джерелаАнотація:
Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2011.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 75).
Tilt-up construction is becoming more popular in the United States due to its ease of construction, reliability, and relatively low construction and maintenance costs. In its most typical form, a concrete panel is cast on the ground. After the concrete sets and has reached a prescribed compressive or flexural strength, a crane lifts the panel off the ground and hoists it into place. The flexural stresses during liftoff are often times greater than those corresponding to service loads. Concentrations of high shear stress and the associated punching shear in the vicinity of the pick points could result in pullout. For these reasons, it is particularly important to design the concrete and steel reinforcement to handle the flexural and shear stresses associated with panel erection. This thesis investigates the flexural stresses and punching shear of a concrete panel designed for tilt-up. Finite element models confirm static hand calculations, and experimental results indicate that these models appropriately predicted erection stresses. The acceptability of the design provided is confirmed.
by Matthew P. Bono.
M.Eng.
40
Nelson, Erik Walter. "Combined Compression and Shear Structural Evaluation of Stiffened Panels Fabricated Using Electron Beam Freeform Fabrication." Thesis, Virginia Tech, 2008. http://hdl.handle.net/10919/43583.
Повний текст джерелаАнотація:
Unitized aircraft structures have the potential to be more efficient than current aircraft structures. The Electron Beam Freeform Fabrication (EBF3) process can be used to manufacture unitized aircraft structures. The structural efficiency of blade stiffened panels made with EBF3 was compared to panels made by integrally machining from thick plate. The panels were tested under two load cases in a combined compression-shear load test fixture. One load case tested the panels' responses to a higher compressive load than the shear load. The second load case tested the panels' responses to an equal compressive and shear load. Finite element analysis was performed to compare with the experimental results. The EBF3 panels failed at a 18.5% lower buckling load than the machined panels when loaded mostly in compression but at an almost two times higher buckling load than the machined panels when the shear matched the compressive load. The finite element analysis was in good agreement with the experimental results prior to buckling. The results demonstrate that the EBF3 process has the capabilities of manufacturing stiffened panels that behave similarly to machined panels prior to buckling. Once the EBF3 panels buckled, the buckled shape of the EBF3 panels was different from the machined panels, generally buckling in the opposite direction of what was observed with the machined panels. This was also expected based on the finite element analysis. The different post-buckling response between the two manufacturing techniques was attributed to the residual stress and associated distortion induced during the EBF3 manufacturing process.Master of Science
41
Woo, Thomas Robert. "Effects of Seawater on the Mechanical Behavior of Composite Sandwich Panels Under Monotonic Shear Loading." DigitalCommons@CalPoly, 2012. https://digitalcommons.calpoly.edu/theses/898.
Повний текст джерелаАнотація:
Abstract
Salt water environments are very harsh on materials that are used within them. Many issues are caused by either corrosion and/or internal degradation to the materials themselves. Composites are better suited for this environment due to their high strength to weight ratios and their corrosion resistance, but very little is known about the fracture mechanics of composites. The goal of this study is to gain a better understanding for the behavior of a composite boat hull under a shear loading, similar to the force water applies on the hull as the boat moves through the water; then attempt to strengthen the composite sandwich panel against the shear loading.
A parametric study was conducted to investigate monotonic in-plane shear loading for composite sandwich panels used in commercial naval vessels. In order to model a conventional composite boat hull, test specimens were composite sandwich panels made of a Divinycell H100 foam core with four layers of fiberglass on both sides of the core. Specimens were tested under a monotonic loading with a rate of 0.2 in/min, and tested until complete failure using the standard test.
Seawater specimens were manufactured in the same manner as the original test specimens, but then were submersed in either filtered seawater or the ocean. The differences between the filtered pieces and the ocean allowed us to determine if any changes found in the composite sandwich panels were related to environment conditions or if the changes were related to the saltwater interaction itself. To create these different environments the seawater specimens were taken to the Avila pier where 36 specimens were placed in a tub that was fed filtered saltwater, while 30 specimens were placed in a plastic mesh with weights and lowered to a depth of approximately 30 ft. in the ocean. Three specimens were then removed at monthly intervals from both filtered and ocean environments.
Shear Keys were created as a method to strengthen the composite sandwich panels against the shear force that the previous specimens had been tested to. Eight Shear Keys were then placed into groves cut into the foam core (four on each side) and the four fiberglass layers were laid on top.
Testing showed that the seawater did have an initial effect on the composite sandwich panels. The filtered pieces showed a decrease in yield strength and stiffness the longer they were subjected to the seawater. The raw unfiltered pieces placed in the ocean saw an even higher decrease in their yield strength and decrease in stiffness. However, for both the unfiltered and raw specimens there was an increase in the ultimate strength and fracture point of the specimens. The effects of the sea water seemed to taper off after the 3rd month however.
The Shear Key specimens were tested with a 4mm and an 8mm Shear Key. The 8mm Shear Keys showed a decrease in shear strength, which was primarily due to removing too much material from the core and weakening the specimen. It was concluded that the decrease in area created a force concentration at the deepest part of the Shear Key causing the premature failure. The 4mm Shear Key showed an increase in the yield strength, ultimate strength, and fracture point. A finite model was built to simulate the original test specimen along with the 4mm and 8mm Shear Key cases, and the results were compared to the experimental results.
The numerical results showed that it was possible to relate the experimental results to the linear or elastic portion of the plots. There was a difference between the maximum displacement of the model and the actual specimens, but this was attributed to potential inaccurate comparison of the loading on the model compared to the actual specimens. The correlation between the model itself and the experimental data was close enough to conclude that it could be used for predicting baseline trends.
Further investigation of the specimens should include looking into the effects of a cyclic shear loading on the specimens. This combined with the seawater element used in this thesis would provide further insight to the initial degradation seen in the seawater specimens, and could potentially provide a closer relation to current hull failures. In addition to including a cyclic loading another numerical model should be created. A model that could be constrained both locally and globally would provide more accurate results. The FEM should also include the ability to run a crushable foam core model within the solver which would also increase the accuracy of the numerical solution.
42
Chemlali, Alexander, and Rickard Norberg. "Shear cracks in reinforced concrete in serviceability limit state." Thesis, KTH, Betongbyggnad, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-169591.
Повний текст джерелаАнотація:
Shear cracks are formed when high oblique tensile stresses, e.g. in thin webs, exceed the tensile strength. A known example of this phenomenon is the extensive shear cracks that were found on the box-girder bridges Gröndal and Alvik, which were mainly caused by insufficient amount of shear reinforcement. In order to avoid this incident (inadequate amount of shear reinforcement), the reinforcement stress is often being assumed as a ultimate limit load in order to fulfill requirements regarding crack control in the service-ability limit state (SLS). This method has led to a overestimation of the reinforcement amount in bridge-design. The aim of this master thesis is therefor to study the shear crack phenomenon and investigate if the amount of shear reinforcement in bridges can be reduced. The first part of this thesis studies the shear cracking behavior in concrete in a plane stress state, while the second part focus how design standards as well as manuals treats shear cracks. Shear cracking in the reinforced concrete panels has been studied with non-linear finite element analysis and compared to experimental testings performed by the University of Toronto. Three different loading conditions for the panels has been analyzed: pureshear, compression or tension combined with shear. The panels are to represent parts of a web in a box-girder bridge that are subjected to in-plane stresses. The non-linear finite element analysis was performed in the FE-program Atena where mainly the crack propagation and crack pattern were studied. The material model in Atena is a smeared crack model with either fixed or rotated crack direction. The panel analysis, in SLS, gave various results. For loading conditions pure shear and tension/shear, the response of the FE-analysis gave a similar result regarding crack pattern but differed in size of crack width. For compression/shear, only micro-cracks developed and did not reflect the result from the real panel tests. This may be the consequence of a too stiff FE-model and the fact that, in the real tests, some cracks occurred due to out-of-plane bending. With methods described in Eurocode 2 and the Swedish handbook for EC2, a shear crack calculation model was created in order to determine the reinforcement stress and crack width. As a reference for the shear crack calculations, a wing structure (1 m strip) has been used which is part of a railway bridge located in Abisko. These calculations were done in order to investigate if the amount of shear reinforcement could be reduced and at the same time fulfill crack control demands in SLS. The bridge department at Tyréns AB concluded, according to a truss model, that the wing section should be reinforced with a amount of 14.1 cm2/m2 while our model showed that the crack width demand could be fulfilled with a equivalent amount of 9.82 cm2/m2, i.e. a reduction around 30%.
43
Murphy, A. "Accurate and efficient buckling and post buckling analysis of fuselage panels loaded in shear and compression." Thesis, Queen's University Belfast, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.273230.
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Lin, Weiqing. "Buckling and postbuckling of flat and curved laminated composite panels under thermomechanical loadings incorporating non-classical effects." Diss., Virginia Tech, 1997. http://hdl.handle.net/10919/40240.
Повний текст джерелаАнотація:
Two structural models which can be used to predict the buckling, post buckling and vibration behavior of flat and curved composite panels under thermomechanical loadings are developed in this work. Both models are based on higher-order transverse shear deformation theories of shallow shells that include the effects of geometric nonlinearities and initial geometric imperfections. Within the first model (Model I), the kinematic continuity at the contact surfaces between the contiguous layers and the free shear traction condition on the outer bounding surfaces are satisfied, whereas in the second model (Model II), in addition to these conditions, the static interlaminae continuity requirement is also fulfilled.
Based on the two models, results which cover a variety of problems concerning the postbuckling behaviors of flat and curved composite panels are obtained and displayed. These problems include: i) buckling and postbuckling behavior of flat and curved laminated structures subjected to mechanical and thermal loadings; ii)frequency-load/temperature interaction in laminated structures in both pre-buckling and post buckling range; iii) the influence of a linear/nonlinear elastic foundation on static and dynamic post buckling behavior of flat/curved laminated structures exposed to mechanical and temperature fields; iv) implication of edge constraints upon the temperature/load carrying capacity and frequencyload/ temperature interaction of flat/curved structures; v) elaboration of a number of methodologies enabling one to attenuate the intensity of the snap-through buckling and even to suppress it as well as of appropriate ways enabling one to enhance the load/temperature carrying capacity of structures.Ph. D.
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Derrick, Nathan Lynn. "Shear and Bending Strength of Cold-Formed Steel Solid Wall Panels Using Corrugated Steel Sheets for Mobile Shelters." Thesis, University of North Texas, 2017. https://digital.library.unt.edu/ark:/67531/metadc1062814/.
Повний текст джерелаАнотація:
The objective of this thesis is to determine if the single sided resistance spot weld (RSW) can be used as a feasible connection method for cold formed steel (CFS) shear walls subject to lateral force of either seismic or wind loads on mobile shelters. The research consisted of three phases which include: a design as a 3D BIM model, connection tests of the resistance spot weld, and full-scale testing of the designed solid wall panels. The shear wall testing was conducted on specimens with both resistance spot weld and self-drilling screws and the results from tests gave a direct comparison of these connections when the solid wall panel was subjected to in-plane shear forces. The full-scale tests also included 4-point bending tests which was designed to investigate the wall panel's resistance to the lateral loads applied perpendicularly to the surface. The research discovered that the singled sided resistance spot weld achieved similar performance as the self-drilling screws in the applications of CFS wall panels for mobile shelters. The proposed single sided resistance spot weld has advantages of low cost, no added weight, fast fabrication, and it is a feasible connection method for CFS wall panels.
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Svensson, Meulmann Sebastian, and Egzon Latifi. "Modelling and testing of CLT panels for evaluation of stiffness." Thesis, Linnéuniversitetet, Institutionen för byggteknik (BY), 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-104766.
Повний текст джерелаАнотація:
The use of timber in building structures is steadily increasing. cross laminated timber (CLT) is an engineered wood product made of an uneven number of layers of lamellas glued at an angle of 90 degrees to each other. This gives CLT high stiffness and strength to bending in all directions, and capability of taking load both in-plane and out-of-plane. Due to the large size of CLT elements, they allow for quick assembly of strong structures. Due to both economic and environmental reasons it is important for producers of CLT to optimize the use of the wood material by using the timber with higher stiffness and strength where it is most needed. This thesis is about evaluating the bending and shear stiffness of CLT elements, when used as plates, depending on the quality of wood used in the different layers. Four-point bending tests are carried out on elements of different compositions and a parametrized finite element model is created. Thus, the model is validated on the basis of experimental tests to evaluate the influence of different quality of different layers. The measured dynamic MoE proved to have good potential to be used as the longitudinal bending stiffness in an FE-model, with a deviation from the experimental tests of less than 1%. There is a strong correlation between the bending stiffness and bending strength of the plates. The effective rolling shear modulus in pine was calculated to be around 170 MPa for pine of dimension 40 x 195 mm2 . Grading the boards into two different classes used for different layers proved to increase the MoE of the plates by 11-17% for 3- and 5-layer CLT.
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Palmieri, Giulia. "Diagonal compression tests on masonry panels reinforced with composite materials FRCM." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2017.
Знайти повний текст джерелаАнотація:
In the last years, due to many severe seismic events, it becomes more and more important to understand the structural performance of masonry structures subjected to seismic actions and structural reinforce became an important task in civil engineering. The developments of innovative techniques for structural retrofitting represent a great change in order to reduce the seismic vulnerability of masonry buildings. Beside the traditional reinforce techniques, new reinforce born such as Fiber Reinforced Polymer (FRP) and Fiber Reinforced Cementitious Matrix (FRCM)
The aim of this thesis is to study the shear strength of masonry panels, subjected to in-plane actions, reinforced with FRCM.
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Khan, Akram. "Composite Behaviour of Normalweight and Lightweight Concrete Panels With Partially Embedded Light-Gauge Steel Channels." Thesis, University of New Brunswick, 2010. http://hdl.handle.net/1882/1092.
Повний текст джерелаАнотація:
This research investigates prefabricated light-gauge steel and concrete panels using
reliable and commercially viable shear connectors. An analytical and experimental
investigation was undertaken to study the flexural behaviour of light-gauge steel and
concrete composite panels under uniform pressure. Normalweight and lightweight
concrete panels were fabricated by embedding 16-gauge 41 mm x 203 mm steel channel
sections (running parallel to each other) to a depth of 38 mm into a 64 mm thick
concrete slab. Push-out tests were also conducted to evaluate the efficiency of three
types of shear connection mechanism; natural surface bonding, predrilled holes, and
punched holes. Only two types of shear connectors (predrilled holes and punched holes)
were used in the full-scale panel specimens.
Results show that the predrilled holes and punched holes provide full shear transfer
between the steel and concrete. The ultimate load carrying capacity of the lightweight
concrete panels exhibited similar behaviour to the normalweight concrete panels. All the
panels exhibited good load carrying capacity and ductility, and satisfied the
serviceability limit state of deflection. Thus, the proposed panels present a potential for
a commercially viable composite floor system for building construction utilizing a
maximum span of 2330 mm.
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Vora, Hitesh. "Shear Wall Tests and Finite Element Analysis of Cold-Formed Steel Structural Members." Thesis, University of North Texas, 2008. https://digital.library.unt.edu/ark:/67531/metadc9726/.
Повний текст джерелаАнотація:
The research was focused on the three major structural elements of a typical cold-formed steel building - shear wall, floor joist, and column. Part 1 of the thesis explored wider options in the steel sheet sheathing for shear walls. An experimental research was conducted on 0.030 in and 0.033 in. (2:1 and 4:1 aspect ratios) and 0.027 in. (2:1 aspect ratio) steel sheet shear walls and the results provided nominal shear strengths for the American Iron and Steel Institute Lateral Design Standard. Part 2 of this thesis optimized the web hole profile for a new generation C-joist, and the web crippling strength was analyzed by finite element analysis. The results indicated an average 43% increase of web crippling strength for the new C-joist compared to the normal C-joist without web hole. To improve the structural efficiency of a cold-formed steel column, a new generation sigma (NGS) shaped column section was developed in Part 3 of this thesis. The geometry of NGS was optimized by the elastic and inelastic analysis using finite strip and finite element analysis. The results showed an average increment in axial compression strength for a single NGS section over a C-section was 117% for a 2 ft. long section and 135% for an 8 ft. long section; and for a double NGS section over a C-section was 75% for a 2 ft. long section and 103% for an 8 ft. long section.
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Wendel, Erik. "Evaluation of potential for metal/polymer/metal sandwich material as outer panels for trucks." Thesis, KTH, Materialvetenskap, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-247958.
Повний текст джерелаАнотація:
Reducing the weight of the truck vehicle conveys more cargo to be carried by thetrailer. This has a significant impact on the efficiency of the transport lowering both the total cost of cargo moved and the total carbon dioxide emitted. Half of the body in-white weight of a truck is comprised out of panels made out of thin mild forming steel which cannot be made thinner to reduce weight due to the lowered stiffness it would entail. Sandwich materials have a high stiffness to weight ratio and would for the same panel thickness as regular forming steel have a comparable bending stiffness but lowered weight. This master thesis is intended to be a preliminary study for Scania CV AB on sandwich materials and its potential use as lightweight panels in their trucks. With the intention of investigating whether a commercial sandwich material is capable of filling the role as outer panels of a truck, comparative tests regarding significant matters such as forming and painting was made on identically manufactured demonstrators comparing a sandwich material and a regular forming steel material. The tests identified weaknesses in the current manufacturing process for parts of a sandwich material. Such limitations are problems with painting and joining due to isolated cover sheets, forming problems revealing sink marks likely due to different spring back of the material and hemming flaws due to inadequately optimized hemming technique and anisotropy. Now that more knowledge of sandwich materials has been gained, counter measures for these findings can be made in order to take another step towards lowering the weight of the truck and a more efficient way of transporting goods.Genom att minska vikten på lastbilen frigörs mer last att bäras av släpvagnen. Detta har en betydande inverkan på effektiviteten hos transporten som sänker både den totala kostnaden för transporterad last och de totala koldioxidutsläppen. Hälften aven lastbils rena karossvikt består av paneler gjorda av tunt mjukt formningsstål vilke tinte kan bli tunnare för att minska vikten på grund av den sänkta styvheten som detskulle medföra. Sandwichmaterial har en hög styvhet till viktförhållande och skulle församma paneltjocklek som vanligt formningsstål ha en jämförbar böjstyvhet men sänkt vikt. Denna uppsats är avsedd att vara en preliminär studie för Scania CV AB om sandwichmaterial och dess potentiella användning av lättvitkspaneler i lastbilar.Med avsikt att undersöka huruvida ett kommersiellt sandwichmaterial kan fylla rollen som lastbilens ytterpaneler utfördes jämförande tester med avseende på signifikanta frågor såsom formning och målning på identiskt tillverkade demonstratorer som jämförde ett sandwichmaterial och ett vanligt formningsstål. Testerna identifierade svagheter med materialet samt hur processen behöver anpassas för att kunna använda sandwichmaterialet i rådande tillverkningsprocess. Identifierade problem var bland annat problem med målning och sammanfogning på grund av isolerade ytterskickt i sandwichmaterialet, problem med formning som gav upphov till limdragningar som troligen beror på materialets olika återfjädring samt falsningsfel på grund av otillräckligt optimerad falsteknik och anisotropi. Nu när mer kunskap om sandwichmaterial erhållits kan motåtgärder för de funna resultaten undersökas för att ta ytterligare ett steg mot att sänka lastbilens vikt och därmed få ett effektivare transportmedel.