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1
Al-Ansari, Mohammed Salem, and Muhammad Shekaib Afzal. "Structural analysis and design of irregular shaped reinforced concrete slabs using a simplified design method." Journal of Structural Engineering & Applied Mechanics 3, no. 4 (December 31, 2020): 276–88. http://dx.doi.org/10.31462/jseam.2020.04276288.
Повний текст джерелаАнотація:
This paper presents a simplified method to analyze and design the irregular reinforced concrete slabs based on structural safety and economy. The triangular, trapezoidal, and curved slab sections are selected in this study to be analyzed and designed using a simplified design method approach (SDM) as these sections are the most common type of irregular slab sections used in the construction industry. Flexural design formulas for triangular and curved slabs are derived based on the theoretical principles of plate and yield line theories and ACI building code of design constraints. Numerical examples are presented in this study to illustrate the method capability of designing the most commonly used irregular slabs sections. The complete design of four triangular slabs (TS-1 to TS-4) and four curved slabs (CS-1 to CS-4) is provided in this study. Besides, the required equivalent (triangular and rectangular) shaped sections are provided to deal with irregular trapezoidal slab section. The selected irregular slab sections (triangular and curved slab sections) are also analyzed and designed using the computer software (SAFE) and the results obtained are compared with the numerical solutions. The percentage difference of the simplified method with the finite element software (SAFE) ranges from 4% to 12%. The results obtained for all the selected irregular shaped slab sections indicates that the SDM is a good and quick approach to design irregular (triangular and curved) slab sections.
2
Kigoye, Eriya, and Michael Kyakula. "Load Deflection Relationship of a Solid Slab under the Action of Construction Loads." Advances in Civil Engineering 2022 (March 9, 2022): 1–16. http://dx.doi.org/10.1155/2022/3125920.
Повний текст джерелаАнотація:
Over the past decades, there has been a tremendous improvement in the concrete placement technology in Uganda. The methods have moved from being manual to the use of concrete pumps. A concrete pump is capable of pumping high volumes of concrete per minute. This implies that for small volume slabs before the setting of concrete, the whole weight of the fresh concrete of the upper slab, formwork, and props is transferred to the lower supporting slab. During construction, slabs are stacked with materials like bricks, blocks, sand, and aggregates. Construction loads such as block loads and loads due to props, formwork, and freshly cast solid concrete slabs on the lower floor are usually greater than the imposed loads and are not catered for in design. A baseline survey carried out on 118 randomly selected sites in Kampala revealed that in 87% of the cases, supports are removed from a lower reinforced concrete slab, and then props are put on its top to support a yet to be cast slab on an upper floor. It also revealed that 80.6% of the slabs had construction loads such as bricks, blocks, sand, timber, and aggregates. Deflections were measured using dial gauges for construction loads owing to freshly cast slab and concrete blocks in a physical model of a multistory structure with dimensions of 4 m long, 2 m wide, 2 m high to 2nd level, and 2 m to 3rd level. Loads due to freshly cast concrete were 158% more than unfactored design live loads. The maximum deflection at center of the slab due to a freshly cast slab and blocks loaded instantly was 1.15 mm and 11.815 mm, respectively, compared to the immediate deflection equal to 0.103 mm due to a design-imposed load of 2 KN/m2.
3
Xu, Xiaoqing, and Yuqing Liu. "Load Capacities of Steel and Concrete Composite Bridge Deck Slab with Haunch." Advances in Civil Engineering 2017 (2017): 1–15. http://dx.doi.org/10.1155/2017/3295303.
Повний текст джерелаАнотація:
An innovative steel and concrete composite bridge deck slab using bent bars and epoxy as shear connectors was proposed. Four slab specimens with different types of concrete were fabricated and tested to study the load capacities of positive and negative moment regions of the slabs. The cracking and ultimate loads of the specimens were recorded and compared with the results calculated through the reinforced concrete theory and with the design load of the bridge deck slab. It was found that reinforced concrete theory can generally be applied for the proposed slab as well. The effectiveness of the shear connector design of the proposed slab was validated. Meanwhile, the unfavourable effect of the haunch on the shear capacities of the positive moment region of steel and concrete composite bridge deck slab was observed.
4
Shulyat'ev, Stanislav. "Optimization of foundation solution by full-scale experimental soil-slab interaction." Construction and Architecture 10, no. 3 (September 27, 2022): 1–5. http://dx.doi.org/10.29039/2308-0191-2022-10-3-1-5.
Повний текст джерелаАнотація:
Article considers the case of optimizing design solution for foundation of a 10-storey residential building on sandy soils. Optimization was achieved through experimental work with 2*2*0,2 m reinforced concrete slabs and 5000 cm2 stamps. During slabs testing slab settlements, in concrete and reinforcement, as well as contact pressure under slab were measured. During stamps testing displacements of the stamp and surrounding soil were measured at 21 points. As a result of the tests deflection slab mode, slab-soil contact stresses, changes in radius of curvature, relative deformation of concrete and reinforcement in upper and lower parts of the slab during loading were obtained. Results of experimental data made it possible to select a foundation model, which was later used for foundation design. Recommendations are given for determining soil deformation characteristics, modeling soil-plate interaction, as well as economic efficiency of foundation design solution.
5
Shi, X. M., C. S. Cai, George Voyiadjis, and Zhongjie Zhang. "Design of Ribbed Concrete Approach Slab Based on Interaction with the Embankment." Transportation Research Record: Journal of the Transportation Research Board 1936, no. 1 (January 2005): 181–91. http://dx.doi.org/10.1177/0361198105193600121.
Повний текст джерелаАнотація:
To alleviate the “bump” problem at bridge ends, a ribbed concrete approach slab (similar to slab-on-beam bridge decks) was proposed in place of the pile–column-supported approach span or flat slab system. The effect of given embankment settlement on the structural performance of a ribbed concrete approach slab with a span length of 60 ft and a width of 40 ft was investigated. The approach slab was modeled as a ribbed slab with a beam spacing of 32, 16, and 12 ft. A three-dimensional finite element analysis was conducted to model the interaction between the approach slab and the embankment soil. Finite element modeling techniques that simulate the separation of the slab and soil provide information on the effect of the embankment settlement on structural performance and beam design. The predicted internal forces provide design engineers with a scientific basis to design the approach slab properly, considering different levels of embankment settlements. Current AASHTO code specifications do not provide guidelines to design approach slabs considering the embankment settlement.
6
Konoplianyk, Oleksandr, Nikolay Kotov, and Illia Iliev. "Specific Design Features of Prefabricated Fire-Resistant Floor Slabs Made from Lightweight Concrete." Slovak Journal of Civil Engineering 30, no. 1 (March 1, 2022): 1–7. http://dx.doi.org/10.2478/sjce-2022-0001.
Повний текст джерелаАнотація:
Abstract Reinforced concrete roof and floor structures have the highest heating temperatures and are exposed to the most difficult conditions during fires that occur in buildings and structures. The standardized fire resistance of hollow-core slabs made of heavy concrete from Portland cement is regulated as REI 45 or REI 60. The aim of the work is to develop a composition of lightweight fire-resistant concrete and architectural engineering for floor slab devices. The composition of lightweight fire-resistant concrete made from expanded clay aggregates and alumina cement was developed as a result of the work. The degree of fire resistance of the lightweight concrete composition with a bulk density of 1475 kg/m3 has been practically determined; i.e., REI 90. The structural solution of the floor slab has been improved; at the same time, we propose to develop a slab with a flat section made of lightweight fire-resistant concrete. Such floor slabs, along with an increase in the fire resistance limit, improve the heat-insulating ability of a floor due to a significant reduction in the coefficient of the thermal conductivity of lightweight concrete.
7
Tur, Andrei V. "Large-Size Jointless Concrete Slab-on-Grade with Combined Prestressing." Solid State Phenomena 309 (August 2020): 201–7. http://dx.doi.org/10.4028/www.scientific.net/ssp.309.201.
Повний текст джерелаАнотація:
In the international and national practice of design, a different type of slab on the various types of grade are becoming increasingly common. For such structural elements, shrinkage and temperature influences in combination with low tensile stress, mainly in early age, leads to the risk of cracking in reinforced concrete structures, and as result, a reduction of its durability. The present article describes some of the possible ways of usage of the post-tensioned flat slabs and the rational design procedures to provide their structural reliability. The theoretical background of the punching resistance checking, in the case when the piles support the foundation post-tensioned slabs, presented. For ground floor slabs, an iterative method is given for determining design compression pre-stresses distribution in slab sections, taking into account the restrained effect created by the friction shear stresses in contact between the slab and the base. Besides, the article presents some practical implementations of the post-tensioned slabs as an artificial base in the presence of weak soils and as a large-size ground floor (slab-on-grade) without any joints.
8
RODCHENKO, Oleksandr. "COMPUTER TECHNOLOGIES FOR CONCRETE AIRFIELD PAVEMENT DESIGN." Aviation 21, no. 3 (March 8, 2018): 111–17. http://dx.doi.org/10.3846/16487788.2017.1379439.
Повний текст джерелаАнотація:
The purpose of the research is to develop formulas, expressions and a computer program for concrete airfield pavement design under the impact of all Airbus 380 main landing gears taking into consideration the design factor of tensile stresses at the top and bottom of a concrete slab. The top-down cracking in concrete slabs has not been directly simulated in structural analysis models used for one- and two-layer concrete airfield pavement design by the Ukrainian Standard. Empirical formulas for the calculation of top tensile stress and the coverages to failure using the criterion of top tensile stress are obtained. Computer program “Aerodrom 380” has been developed for the design of concrete airfield pavement thickness. It provides the required thickness of a concrete slab needed to support an Airbus 380 over a particular subgrade and uses the bottom and top tensile stresses as design factors. “Aerodrom 380” contains a fatigue function for determining the number of coverages to failure permissible for a concrete slab before it has top-bottom and bottom-up cracks. The results obtained with this program are compared to other solutions using the Ukrainian Standard SNiP 2.05.08–85, “LIRA-SAPR”, software and the FAARFIELD computer program. The anticipated life of a concrete airfield pavement calculated using computer program “Aerodrom 380” is about 70% of the FAARFIELD pavement life.
9
Unamba, K. U. "Probabilistic Assessment of Sandwiched Concrete Slabs in Deflection." International Journal for Research in Applied Science and Engineering Technology 9, no. 9 (September 30, 2021): 2052–58. http://dx.doi.org/10.22214/ijraset.2021.38248.
Повний текст джерелаАнотація:
Abstract: This study presents a probabilistic evaluation of concrete sand-witched hollow core slabs in accordance with the design requirements of BS8110 (1985; 1997) and Eurocode 2 (2008). The First Order Reliability Method (FORM) was used in computing the probability of failure. For the deflection failure, the effect of varying the load ratio and the breadth of slab on the reliability analysis were carried out at the following values of concrete strengths ݂ܿu: 25N/mm2 , 30 N/mm2 , 40 N/mm2 , 50 N/mm2 . The results indicate that deflection characteristics of the slab are directly affected by the concrete strength, loadings, breadth of slab selected. Thus, the deflection of the slab increases with increases in loading, hollow core, breadth of slab and decrease in concrete strength. This shows that the safety index of reinforced sandwiched concrete slab in deflection generally decreases as the load ratio and breadth of slab increase for each combination of concrete strength. Keywords: Probabilistic Analysis, Sandwiched Concrete, Reliability Analysis, Stochastic Model, FORM
10
Kamble, Rushikesh U., Musharaff S. Shaikh, Shagufa M. Sayyed, Ansar A. Sayyad, and Prof Hari D. Aiwale. "Comparative Study of Bubble Deck Slab with Conventional R.C.C Slab." International Journal for Research in Applied Science and Engineering Technology 10, no. 5 (May 31, 2022): 183–87. http://dx.doi.org/10.22214/ijraset.2022.42141.
Повний текст джерелаАнотація:
Abstract: When designing a reinforced concrete structure a primary design limitation is the span of the slabbetween the columns. Designing large spans between columns often requires very thick slabs thereby increasing the weight of the structure by requiring use of larger amounts of concrete. Heavier structures are less desirable than light weight structures in seismically active regions because a larger dead load for a building increases the magnitude of inertia forces which the structure must resist as larger dead load contributes to higher seismic weight. A new solution to reduce the weight of concrete structures and increase the span of reinforced concrete is “Bubble Deck Technology''. Bubble Deck Slab is a futuristic method which can effectively eliminate all the concrete from the middle of slab by replacing it with high density polyethylene balls. In this technique reinforcement mesh acquires, allocates and attaches the balls at exact position and also stabilizes the lattice. By these techniques the structural weight can be reduced from 25% to 50%. The main aim of our study is to compare bubble slab and conventional slab under cost analysis, stress and deflection. In our project, we designed both the slabs using AutoCAD and tested our design using Ansys software. The advantages are less energy consumption - both in production, transport and carrying out, less emission - exhaust gases from production and transport, especiallyCO2. Keywords: Bubble Deck Technology, HDPE Balls, AutoCad, Ansys, Conventional RCC Slab,Stress and Deflection.
11
Muhammad Khairussaleh, Nor Ashikin, Ng Kah Hoe, Roslina Omar, and Gerald A. R. Parke. "The Effect of Area Loading and Punching Shear on the Reinforced Concrete Slab Containing Spherical Plastic Bubble Balls." Key Engineering Materials 912 (March 4, 2022): 211–23. http://dx.doi.org/10.4028/p-m89355.
Повний текст джерелаАнотація:
The reinforced bubble deck slab or BubbleDeck is a unique system that improves the building design and performance of structures. This slab structure is a reinforced concrete structure that contains high-density polyethene (HDPE) hollow spherical plastic bubble balls with less concrete volume compared to a normal reinforced concrete slab. The system can facilitate up to a 50% longer span compared to a conventional reinforced concrete solid slab. But, eliminating the deadweight concrete may affect the actual performance of the slab structure such as its flexural and shear capacity. Thus, this paper investigates the effect of area loading and punching shear loading on the reinforced bubble deck slab in terms of flexural performance. The square slabs with 1200mm by 1200mm for width and length with a thickness of 230mm were designed as a one-way supported slab. A total of 36 HDPE hollow spherical plastic bubble balls with a 180mm diameter were placed in each bubble deck slab specimen. The high yield steel DA6 BRC reinforcement steel bar meshes and Grade-30 concrete were used for the slabs. The experimental results of the flexural performance of the reinforced bubble deck slab that were subjected to the static area and punching shear loadings are presented. The effect of the load applied in the experiments on the slabs such as flexural strength, bending stiffness and load-deflection behaviour were discussed including the crack propagation and crack pattern.
12
Eratodi, I. Gusti Lanang Bagus, Ali Awaludin, Ay Lie Han, and Andreas Triwiyono. "Evaluation and Study of Prestressed Slab Structure Precast Modular Concrete." MEDIA KOMUNIKASI TEKNIK SIPIL 26, no. 1 (July 30, 2020): 44–51. http://dx.doi.org/10.14710/mkts.v26i1.27765.
Повний текст джерелаАнотація:
Prestressed precast modular concrete slabs function rigid pavement, supporting vehicle loads above it on subgrade with relatively low bearing capacity. This slab measures 2000 x 850 x 150 mm3 of regular reinforced concrete (old production) or prestressed concrete (new production) quality K-500. After several times of use, damage occurs mainly at the end of the slab in the form of spalling. The objectives of the study and evaluation were: (1) observing damage; (2) material quality data; (3) numerical modeling by taking into account material properties, loading and soil conditions; and (4) providing slab design recommendations including materials and geometrics. The method of study and evaluation of slab damage was done by observing the damage, taking concrete core-case and testing it in the laboratory, and modeling the slab structure with various parameters (soil data, concrete quality and slab geometry). Field observations and analysis results show that concrete slab spalling occurs initially at the edge (850 mm wide) which in turn causes the effectiveness of the pre-tension force to be suboptimal and finally the concrete spalling volume increases. Apart from the frequency of collisions during installation and slab deformation when supporting vehicle loads. Concrete spalling problems also due to inappropriate concrete quality.
13
Fillo, Ľudovít, Jaroslav Halvonik, and Viktor Borzovič. "Punching of Concrete Flat and Foundation Slabs." Transactions of the VŠB – Technical University of Ostrava, Civil Engineering Series. 14, no. 1 (June 1, 2014): 1–7. http://dx.doi.org/10.2478/tvsb-2014-0001.
Повний текст джерелаАнотація:
Abstract This paper deals with punching of flat and foundation slabs. Te paper presents limiting values of maximum punching resistance of these slab structures with sudden and brittle mode of failure. In the paper are introduced graphs for design of flat and foundation slab thickness depending on load intensity, span length and reinforcement ratio.
14
Vaitkus, Audrius, Rita Kleizienė, Viktoras Vorobjovas, and Donatas Čygas. "Mixture Strength Class and Slab Dimensions’ Effect on The Precast Concrete Pavement Structural Performance." Baltic Journal of Road and Bridge Engineering 14, no. 3 (September 26, 2019): 443–71. http://dx.doi.org/10.7250/bjrbe.2019-14.452.
Повний текст джерелаАнотація:
Mechanical properties and slab dimensions of concrete are the major parameters based on which the performance of concrete pavement structures is predicted. Precast concrete pavement, as one of the most common modular pavement type, is the advanced next-generation technology characterised as high quality, durable, quickly built and easily maintained. The service conditions of precast concrete pavement (traffic loading and environmental effects) are similar to the conventional cast-in-place jointed plain concrete pavement. Thus, the precast concrete pavement structural design is similar to that of jointed plain concrete pavement. There are several concepts for the design of concrete pavement structure. However, they are based on different distress evaluation and critical stresses estimation methods assuming the slab dimensions that for jointed plain concrete pavement are within the wide joint spacing range from 3.5−6.0 m. The objective of this paper is to analytically evaluate the effect of concrete mixture mechanical properties on the thickness and dimensions of precast concrete pavement slab. Also, define the minimal thickness of precast concrete slab dependent on slab dimensions and concrete mixture mechanical properties elastic modulus and tensile splitting strength. The analysis is based on bearing capacity, performance and fatigue boundary conditions as reported by semi-probabilistic pavement design method Richtlinien für die rechnerische Dimensionierung von Betondecken im Oberbau von Verkehrsflächen RDO Beton 09. Considering that, concrete mixture has significant effects on pavement performance; the composition of concrete was also discussed in this paper. The optimal slab dimensions, concrete layer thickness, and base layer type is suggested in this paper. The outcomes of this analysis apply to the production of precast concrete pavement slabs.
15
Miller, Olga, Oliver Gericke, David Nigl, Daria Kovaleva, and Lucio Blandini. "Simulation-Based Investigations of the Load-Bearing Behavior of Concrete Hollow Sphere Slabs Exposed to Fire." Fire 5, no. 6 (November 22, 2022): 197. http://dx.doi.org/10.3390/fire5060197.
Повний текст джерелаАнотація:
This paper concerns the investigations of the flexural capacity of concrete slabs with integrated concrete hollow spheres that are subjected to fire and their mass saving potential compared to solid slabs. (1) Background: The overuse of concrete in construction contributes considerably to global CO2 emissions; therefore, the potential for mass reduction in structural components must be fully exploited. However, the design regulations for weight-minimized components, particularly slabs with internal voids, are often not explicitly covered by standards, such as the fire design standard relevant to this paper. (2) Methods: Based on the design guidelines for statically determinate structures in Eurocode 2-2 and DIN 4102-4, a solid slab and a concrete slab with concrete hollow spheres are designed and evaluated with regard to their weight and flexural capacity when subjected to fire. The temperature profiles within the slab cross-section exposed to fire are simulated using ABAQUS finite element software, considering the physically nonlinear, temperature-dependent material behavior of concrete and steel. Using these results, the strain distribution corresponding to the maximum flexural moment is iteratively determined at the weakest cross-section, which exhibits the largest void. (3) Results: All components show sufficient flexural capacity for the target fire duration of 90 min. (4) Conclusion: In the context of this study, the design guidelines according to Eurocode 2-2 and DIN 4102-4 are proven to be fully applicable also for concrete hollow sphere slabs.
16
Zhang, Yan Kun, Shao Yu Zhang, and Xiao Er Zhou. "Finite Element Analysis on Mechanical Properties of Light-Weight Aggregate Concrete Composite Slab." Advanced Materials Research 250-253 (May 2011): 168–71. http://dx.doi.org/10.4028/www.scientific.net/amr.250-253.168.
Повний текст джерелаАнотація:
By finite element method, experimental results of the light-weight aggregate concrete composite slab are compared with the numerical simulation.. On the basis, nine composite slab specimen are designed. The loading process, includes the slab cracking, the yielding of steel plates, damaging of slabs are simulated, and the influencing factors, such as male pin, thickness of deck, and spacing of transverse shear reinforcing bars, etc. is studied. At last, the spacing of transverse shear reinforcing bars of light-weight aggregate concrete composite slab is given, and it is useful to the engineering design.
17
Nachiar S, Sindhu, Anandh S, and Jeyem Veerarajan. "Study on Behaviour of Cellular Concrete Slab." International Journal of Engineering & Technology 7, no. 2.12 (April 3, 2018): 420. http://dx.doi.org/10.14419/ijet.v7i2.12.11509.
Повний текст джерелаАнотація:
Generally for any construction, normal conventional concrete is used to obtain required strength as per design. In the construction industry, now a day’s many construction techniques are in practice to minimise the self weight of concrete, thereby reducing the size of structural elements. One of the most widely adopting techniques is use of light weight concrete. But use of these light weight concrete do not fulfil the strength requirement as per the design of the structure. Hence it is used only as non-load bearing structural elements in the field. In view of this, in this study the attempt has been made to introduce the air voids in conventional concrete without compromising the strength. In this work the air voids are introduced in the concrete slabs and it is tested in the laboratory to know the performance. For this purpose, the slab of the size of 600mm x 600mm x 100mm is prepared with the voids of diameters 30mm, 35mm and 40mm. The voids are introduced in the concrete slab in four different configurations (line, X, I and matrix) to prepare the cellular elements. The normal and cellular slabs are tested under single point loading and the effect of various configurations is studied at the age of 28 days. From the test results, it was found that the slab with void volume of 1.59% shows the lowest stiffness and the slab with void volume of 2.28% shows the highest stiffness.
18
Morin, Richard, Ghfran Al Chami, Richard Gagné, and Benoit Bissonnette. "Design Considerations and Innovative Approach for Restoration of Historic Landmarks in Old Montreal." MATEC Web of Conferences 199 (2018): 07003. http://dx.doi.org/10.1051/matecconf/201819907003.
Повний текст джерелаАнотація:
Restoration of some streets in Old Montreal is achieved using granite pavers bonded with a mortar bed to a concrete slab. The technique was originally used for the pavement of St-Paul Street with stone bricks back in the 1800's. A similar approach is being used in 2016 to renovate the very same street, except for the materials used in casting the foundation slab. In order to space out the expansion joints and prevent drying shrinkage cracking, fibre reinforcement and an expansive component are incorporated in the concrete. The concept was successfully used in bridge deck rehabilitation projects such as Girouard Overpass deck overlay. The basic principle of this approach is to generate a chemical expansion in the concrete (200 to 300 gm/m) using an expansive component, and to restrain the generated expansion through the combined action of ordinary peripheral steel reinforcement in the slab and steel fibre reinforcement in the concrete. The objective is to mitigate shrinkage stresses by keeping the strain balance as low as possible and allowing the concrete additional time to develop sufficient tensile strength, such that the stresses induced in the concrete slabs will remain lower than the concrete tensile strength.Restraint of expansion by the steel fibres and the peripheral reinforcement induces an initial compressive stress in the concrete slab. A part of this stress is used to compensate for the drying shrinkage, whereas the remaining part (if any) is used to resist incidental restrained deformation (e.g. thermal strains) cracking. Concrete mixture proportioning, placement, and curing need to be optimized in order to achieve enough expansion to adequately control cracking due to restrained shrinkage. After proper moist curing of the slab, the pavers are bonded to its top surface using a latex-modified mortar (latex to cement ratio of about 11% by mass). The latex-modified mortar used as a levelling bed underneath the pavers has a low vapour permeability that partially seals the concrete surface and further contributes to minimize drying shrinkage cracking. Since 2011, various historic landmarks in the City of Montreal have been restored using concrete containing an expansive component. To this date, monitoring and performance reports have showed that the chemical prestress approach is quite effective in decreasing shrinkage cracking in paved street foundations, thereby allowing the placement of longer slabs with significantly fewer expansion joints.
19
Uglyanitsa, Andrey. "Construction of Buildings and Structures on Rock Concrete Compensation Slabs when Building in Subsided Areas of Abandoned Coal Mines and Open Pits." E3S Web of Conferences 174 (2020): 01058. http://dx.doi.org/10.1051/e3sconf/202017401058.
Повний текст джерелаАнотація:
For building in subsided areas of abandoned coal mines and open pits on soils damaged by anthropogenic impact and mining operations, it is proposed to base buildings and structures on a three-layer slab founda- tion including: a solid reinforced concrete foundation slab, a sub-ballast of ground overburden burnt rocks and a rock concrete compensation slab lo- cated between them. During subsidence of damaged soils, the rock concrete compensation slab, collapsing and increasing in volume, fills the sinkhole lens under the building with pieces of rock concrete, protecting the rein- forced concrete foundation slab from destruction. It was experimentally es- tablished that for the production of rock concrete compensation slabs, ce- ment rock concrete with aggregate of ground burnt rocks with a coarse frac- tion (–20+10) mm and a fine fraction (−0.63) mm should be used; the ratio of the percentage mass fraction of coarse and fine fractions being 25/75 and 50/50 and the cement-water mass ratio C:W being 1:0.5. The reinforced concrete compensation slabs of the recommended composition can take a design load of up to 9-11 MPa in dry and up to 8-9 MPa in water-saturated conditions. The use of ground overburden burnt rocks for the manufacture of rock concrete compensation slabs and sub-ballast will allow utilizing overburden burnt dumps and improving the environmental situation when building in subsided areas of abandoned mining enterprises.
20
Xu, Bangshu, Wanzhi Zhang, Jie Mei, Guangyao Yue, and Laihua Yang. "Optimization of Structure Parameters of Airfield Jointed Concrete Pavements under Temperature Gradient and Aircraft Loads." Advances in Materials Science and Engineering 2019 (April 24, 2019): 1–11. http://dx.doi.org/10.1155/2019/3251590.
Повний текст джерелаАнотація:
Daily changing temperature causes significant thermal stress in concrete pavement. Tensile stress obtained can exceed flexural tensile strength when the concrete slabs are subjected to large temperature gradient and traffic loads, resulting in pavement damages. In this paper, maximum tensile stresses in concrete slabs with different slab sizes, thicknesses, and length to width (L/W) ratios were investigated by using the finite element (FE) method. The important parameters in the design of concrete pavement are the flexural tensile strength and the fatigue limit. By analyzing the comparison results between the maximum tensile stress and the fatigue limit, the optimum slab size and the critical thickness were determined. The results indicate that the maximum tensile stress obtained is higher for larger slab size with thin thickness. Furthermore, to reduce cutting work and the amount of dowel bars, the optimum slab sizes of the regional airport concrete pavement are recommended as 4 m × 4 m to 6 m × 6 m. The critical thicknesses of 4 m × 4 m slab and 6 m × 6 m slab are determined as 28.2 cm and 34.7 cm, respectively, based on the most unfavorable coupling between positive and negative temperature gradients and the Boeing 737–800 aircraft load. Moreover, the maximum tensile stress increases as the L/W ratio increases. When the slab length is less than 6 m, it is better to use square slab in airport jointed concrete pavement (JCP).
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César, Andrés, and Mauricio Pradena. "Sustainable Engineering: Load Transfer Characterization for the Structural Design of Thinner Concrete Pavements." Sustainability 12, no. 21 (November 3, 2020): 9153. http://dx.doi.org/10.3390/su12219153.
Повний текст джерелаАнотація:
Concrete pavements are characterized by their high durability and low conservation costs. However, concrete production causes large amounts of harmful emissions. In this context, short slab pavements allow us to reduce the slab thickness and the amount of concrete used in their construction. These benefits are only valid if the design assumptions are fulfilled, one of which is the provision of enough Load Transfer Efficiency (LTE) by the aggregate interlock. However, the current design method for short slabs does not relate the LTE with the Crack Width (CW) under the joints. This can jeopardize the sustainable benefits of short slabs. The objective of this study is to propose a method to develop the LTE–CW relationship for the short slabs’ design. The sustainable and accessible approach adopted in the proposal represents a paradigm shift compared to the traditional methods, which are limited to laboratories with sufficient resources to perform real-scale testing. The results show that it is possible to develop the LTE–CW relation in a sustainable manner. Furthermore, the aggregates that fulfill the technical specifications for pavements provide enough LTE when most of the joints are activated. When that happens, short slab pavements reduce environmental and human health impacts by 33% and 26%, respectively.
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Mamontov, Alexandr V., Vladimir N. Nefedov, Igor V. Nazarov, Valentin P. Simonov, and Sergey A. Khritkin. "The foam concrete temperature measuring during its microwave heat treatment." Izmeritel`naya Tekhnika, no. 4 (2021): 44–48. http://dx.doi.org/10.32446/0368-1025it.2021-4-44-48.
Повний текст джерелаАнотація:
The actual problem of accelerating and reducing the energy costs of the foam concrete slabs heat treatment technological process is considered. It is shown that to solve this problem, it is advisable to use the microwave radiation energy as a heat source. The main advantages of the microwave method of foam concrete slabs heat treatment in comparison with traditional methods are considered. The design of a microwave installation for the foam concrete slabs heat treatment has been developed. The installed microwave radiation sources have energy outputs in the form of a rectangular waveguide openings, which are used as radiating antennas. Huygens-Kirchhoff method was used to calculate the temperature distribution on the foam concrete slab surface; the method of loaded long lines was used to calculate the temperature distribution over the foam concrete slab thickness. A method for measuring the foam concrete slab temperature distribution is proposed. The results of theoretical and experimental temperature distribution studies on the surface and the cross-section of foam concrete slab with a width of 1500 mm, a height of 1000 mm and a thickness of 200 mm, a density of 1000 kg/m3 on the electromagnetic fields oscillation frequency of 2450 MHz are shown. The obtained experimental results showed a high efficiency of using microwave radiation for the foam concrete slabs heat treatment technological processes. Microwave technologies can be used for heat treatment of products made of concrete, reinforced concrete and polymer composite materials.
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Gupta, Sushant, and Sanjeev Naval. "Analysis of Orthotropic RC Rectangular Slabs Supported on Two Adjacent Edges - A Simplistic Approach." Civil Engineering Journal 6, no. 10 (October 1, 2020): 1992–2001. http://dx.doi.org/10.28991/cej-2020-03091598.
Повний текст джерелаАнотація:
The design of reinforced concrete slabs supported on two adjacent edges involves complex formulations. In this paper, a simplistic approach is presented for designing orthotropic slabs supported on two adjacent edges. Slab supported on two adjacent edges (existing slab) is transformed into a slab supported on three edges (equivalent slab) by taking a mirror image of the yield line pattern of two adjacent edges supported RC slabs about its unsupported edges to get the exact collapse mechanism for the slabs supported on three edges. The equivalent aspect ratio can be used in the equations already developed for the slabs supported on three sides. Ultimate moment carrying capacity of the slab carrying uniform load can be evaluated by using the available analytical formulations of the slab supported on three edges. So, the present approach gives a simplified method to analyse and design the orthotropic RC rectangular slab supported on two adjacent edges using the equations available for slab supported on three adjacent edges. Hence, the simplistic approach will be very helpful for structural designers dealing with analysis and design of slabs supported on two adjacent edges. Doi: 10.28991/cej-2020-03091598 Full Text: PDF
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Hanna, Awad S., and Ahmed B. Senouci. "Design Optimization of Concrete-Slab Forms." Journal of Construction Engineering and Management 121, no. 2 (June 1995): 215–21. http://dx.doi.org/10.1061/(asce)0733-9364(1995)121:2(215).
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Chung, Joo Hong, Hyun Ki Choi, Chang Sik Choi, and Hyung Suk Jung. "Punching Shear Design Method of Voided Slabs." Key Engineering Materials 754 (September 2017): 333–36. http://dx.doi.org/10.4028/www.scientific.net/kem.754.333.
Повний текст джерелаАнотація:
This study presents punching shear design method of voided slab in accordance with arrangement of voids around columns. According to previous studies, the slab-column connection of voided slabs is weaker than that of the solid slab due to the lack of cross-sectional area of concrete by voids. In this study, it is assumed that the arrangement of voids exert influence on the punching shear strength of voided slabs. To verify the assumption, finite element analysis was conducted related with previous test results. The variable of FE analysis was a distance between voids and column face. Based on FE analysis and test results including previous studies, punching shear design method is suggested which can consider the arrangement of voids around columns. The suggested design method is based on the punching shear design method in ACI-318. As a result, it can predict the punching shear strength of voided slabs according to arrangement of voids around column.
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Bakht, Baidar, and Akhilesh C. Agarwal. "Deck slabs of skew girder bridges." Canadian Journal of Civil Engineering 22, no. 3 (June 1, 1995): 514–23. http://dx.doi.org/10.1139/l95-060.
Повний текст джерелаАнотація:
Canadian codes allow the design of concrete deck slabs of slab-on-girder bridges by taking account of the internal arching action that develops in these slabs under concentrated wheel loads in particular. Provided that certain prescribed conditions are met, a deck slab is deemed to have met the design criteria if it is provided with a top and a bottom layer of steel reinforcement with each layer consisting of an orthogonal mesh of steel bars in which the area of cross section of the bars in each direction is at least 0.3% of the effective area of cross section of the deck slab. For deck slabs of bridges having skew angles greater than 20°, the codes require the minimum amount of reinforcement to be doubled in the end zones near the skew supports. Model testing has shown that need for such an increase can be eliminated by providing composite end diaphragms with high flexural rigidity in the horizontal plane. The proposed concept is tested on a model of fibre-reinforced concrete deck without steel reinforcement in which deficiencies in the confinement of the deck slab readily manifest themselves in form of a bending, rather than punching shear, failure. Key words: highway bridges, bridge decks, deck slabs, skew deck, skew bridges, fibre-reinforced concrete decks.
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Paultre, Patrick, and Caroline Moisan. "Distribution of moments in reinforced concrete slabs with continuous drop panels." Canadian Journal of Civil Engineering 29, no. 1 (February 1, 2002): 119–24. http://dx.doi.org/10.1139/l01-076.
Повний текст джерелаАнотація:
Slabs with continuous drop panels between column lines facilitate formwork, make long spans possible in addition to increase punching shear resistance around supports and provide unobstructed spans with minimum structural floor depth resulting in lower floor-to-floor heights. The moment distribution in such slabs is different from that in conventional flat plates or slabs with drop panels systems. Dimensioning according to the current provisions in CSA A23.3-94 is problematic because the continuous drop panels are subject to moments exceeding the minimum values allowed by the Code for conventional slab systems. This analytical study presents the moment distribution in slabs with continuous drop panels in an attempt to provide more realistic transverse moment distribution factors.Key words: reinforced concrete, slab systems, slab design, drop panel, moment distribution.
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Mohammed, Tamara Amer, and Hayder Mohammed Kadhim. "Effect of Pumice Stone and Sugar Molasses on the Behavior of Reinforced Concrete One-Way Ribbed Slabs." Civil Engineering Journal 8, no. 2 (February 1, 2022): 334–47. http://dx.doi.org/10.28991/cej-2022-08-02-011.
Повний текст джерелаАнотація:
The world is currently heading towards sustainability by reducing the amount of concrete, thus reducing the total unit weight. Moreover, design construction requires materials with a higher strength-to-weight ratio. Ribbed slabs and lightweight concrete (LWC) are considered two leading sustainability facilities. This research developed an experimental study to evaluate the effects of concrete type, steel reinforcement ratio, the geometry of ribs, voiding ratio, and slab type on the structural behavior of one-way ribbed slabs. Eight of the one-way slabs were constructed using pumice stone and by-product material sugar molasses (SM), and one slab was constructed using gravel and SM. These slabs were tested under a static two-point load and simply supported until failure. The results showed that using SM with pumice stone instead of gravel led to high strength-lightweight concrete (HSLWC), with a cylinder compressive strength of 42.2 MPa and a density of 1943 kg/m3, which meets the requirements of HSLWC codes. Using HSLWC instead of high-strength normal-weight concrete (HSNWC) decreased the thermal conductivity by 43.55% and the unit weight by 19.31%. Moreover, the ultimate strength of the HSLWC one-way ribbed slab decreased by 17.70%. Overcoming this strength reduction necessitated increasing the steel reinforcement ratio of the ribs from 0.28 to 0.44% in the HSLWC ribbed slab. Changing the number of ribs at the same amount of HSLWC showed a minor effect on the strength capacity of slabs but showed an economic benefit. However, increasing the rib width to reduce the voiding ratio from 44 to 40% resulted in a greater improvement in structural efficiency (SE) of one-way ribbed slab than reducing it from 44 to 33%. Consequently, the optimum rib width was 120 mm. Moreover, using a ribbed slab instead of a solid slab of HSLWC at the same amount of concrete increased the ultimate strength by 130.37%, decreased deflection by 3.99%, and improved SE by 126.46%. Furthermore, experimental results of ultimate load were compared with the ACI 318-19 code design equation. Doi: 10.28991/CEJ-2022-08-02-011 Full Text: PDF
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Buka-Vaivade, Karina, Dmitrijs Serdjuks, Janis Sliseris, Andrejs Podkoritovs, and Raimonds Ozolins. "TIMBER-CONCRETE COMPOSITE RIBBED SLABS WITH HIGH-PERFORMANCE FIBRE-CONCRETE." ENVIRONMENT. TECHNOLOGIES. RESOURCES. Proceedings of the International Scientific and Practical Conference 3 (June 16, 2021): 40–44. http://dx.doi.org/10.17770/etr2021vol3.6551.
Повний текст джерелаАнотація:
Composite of such renewable material as timber and the most popular man-made material as concrete offers many benefits. Such of them are high load-bearing capacity with low dead load and increased structural bending stiffness. Higher specific strength of high-performance concrete in comparison with ordinary concrete ensures more efficient use of the material. Addition of fibres can reduce the fragility and autogenous shrinkage cracks of high-performance concrete and makes it possible to design thinner layers of concrete for timber-concrete composite structures. Ribbed slabs as solution for the floor slabs, allows to reduce material consumption and to integrate engineering communications into the structures. The current study focuses on determining the effect of the use of high-performance fibre reinforced concrete for timber-concrete composite ribbed slabs with adhesive connection between layers, as the most effective connection type for composite action. The effect of the use of high-performance fibre reinforced concrete is determined by comparison of mid-span displacements of the ribbed slabs numerical models. Three-dimensional finite element models of timber and ordinary concrete composite ribbed slab and high-performance fibre reinforced concrete with additional longitudinal reinforcement ribbed slab are validated by experiment data. Developed numerical models makes it possible to predict the dependence of applied load on mid-span displacement in three-point bending with sufficient precision. Obtained results showed, that replacement of ordinary concrete layer by high-performance fibre reinforced concrete in timber-concrete composite ribbed slab with adhesive connection up to 1.68 times decrease vertical mid-span displacements.
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Chebo, Kamal Amin, Yehya Temsah, Zaher Abou Saleh, Mohamad Darwich, and Ziad Hamdan. "Experimental Investigation on the Structural Performance of Single Span Hollow Core Slab under Successive Impact Loading." Materials 15, no. 2 (January 13, 2022): 599. http://dx.doi.org/10.3390/ma15020599.
Повний текст джерелаАнотація:
In Lebanon and many other countries where structures are vulnerable to impact loads caused by accidental rock falls due to landslides, specifically bridges with hollow core slab, it is mandatory to develop safe and efficient design procedures to design such types of structures to withstand extreme cases of loading. The structural response of concrete members subjected to low velocity high falling weight raised the interest of researchers in the previous years. The effect of impact due to landslide falling rocks on reinforced concrete (RC) slabs has been investigated by many researchers, while very few studied the effect of impact loading on pre-stressed structures, noting that a recent study was conducted at Beirut Arab University which compared the dynamic behavior of reinforced concrete and post-tensioned slabs under impact loading from a 605 kg impactor freely dropped from a height of 20 m. Hollow core slabs are widely used in bridges and precast structures. Thus, studying their behavior due to such hazards becomes inevitable. This study focuses on these types of slabs. For a better understanding of the behavior, a full scale experimental program consists of testing a single span hollow core slab. The specimen has 6000 mm × 1200 mm × 200 mm dimensions with a 100 mm cast in a place topping slab. Successive free fall drops cases from 14 m height will be investigated on the prescribed slab having a span of 6000 m. This series of impacts will be held by hitting the single span hollow core slab at three different locations: center, edge, and near the support. The data from the testing program were used to assess the structural response in terms of experimental observations, maximum impact and inertia forces, structural damage/failure: type and pattern, acceleration response, and structural design recommendations. This research showed that the hollow core slab has a different dynamic behavior compared to the post tensioned and reinforced concrete slabs mentioned in the literature review section.
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Wang, Peng, Di Shi, and Pei Ling Sun. "Design of Concrete Voided Slab of Highway Bridge Pretensioned with CFRP Tendons." Applied Mechanics and Materials 578-579 (July 2014): 477–82. http://dx.doi.org/10.4028/www.scientific.net/amm.578-579.477.
Повний текст джерелаАнотація:
The concrete voided slab pretensioned with CFRP tendons is a new type slab for bridge construction. The problems such as the anchorage, loss of prestress, prestressed tendons configuration etc. are discussed, then through the analysis of structure, the characteristics and key points of design methods are put forward. With a 20m span slab as an example, a comparative study is conducted on the concrete voided slab pretensioned with different tendons of CFRP or steel. The analysis shows that the concrete voided slab pretensioned with CFRP tendons is feasible in engineering.
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Saberi, Miad, Charles-Darwin Annan, and Jean-Marie Konrad. "Numerical analysis of concrete-faced rockfill dams considering effect of face slab – cushion layer interaction." Canadian Geotechnical Journal 55, no. 10 (October 2018): 1489–501. http://dx.doi.org/10.1139/cgj-2017-0609.
Повний текст джерелаАнотація:
In this study, the effect of concrete face slab – cushion layer interface behavior on the performance of face slabs in concrete-faced rockfill dams (CFRDs) is investigated using the finite element method. The body of the CFRD is simulated by the cap elastoplasticity model while the interface zone between the concrete face slab and the gravelly cushion layer is simulated explicitly by an advanced interface constitutive model, developed in the framework of critical state soil mechanics and state parameters, and capable of simulating volumetric behavior and stress path dependency. The effect of elastic and elastoplastic material behavior and water level on the stress and displacement responses of the concrete face slab is examined, and the influence of the roughness at the interface area between the concrete face slab at the contact face and the cushion layer on the performance of the concrete face slab is investigated. Comparison of the results with and without the explicit consideration of the interface behavior shows the importance of incorporating advanced constitutive interface modeling in the design and analysis of CFRDs.
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Sherif, Alaa G., and Walter H. Dilger. "Analysis and deflections of reinforced concrete flat slabs." Canadian Journal of Civil Engineering 25, no. 3 (June 1, 1998): 451–66. http://dx.doi.org/10.1139/l97-102.
Повний текст джерелаАнотація:
The results of a test on a full-scale 5 m continuous slab are used to study the methods of analysis and calculation of deflection of reinforced concrete flat slabs. The most commonly used methods for the analysis of flat slabs, namely the equivalent frame method, the prismatic member method, the direct design method, and the finite element method, are critically compared using the results of the slab tested. Based on the comparison with the unbalanced column moments in the test, improvements for the prismatic member method are suggested. For the deflection calculations of cracked reinforced concrete flexural members, three methods are investigated: the effective moment of inertia approach, the mean curvature approach, and the bilinear method given in the CEB manual for deflections. To calculate the deflections of flat slabs as column and field strip deflections, new coefficients for distributing the bending moments between the column and middle strips are proposed.Key words: analysis, deflection, flat concrete slab, test.
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Nguyen, Cong Thanh, and Nhung Hong Tu. "EVALUATING THE EFFECTIVE DESIGN OF REINFORCED CONCRETE FLOOR SLABS IN CIVIL WORKS IN TRA CU DISTRICT – TRA VINH PROVINCE." Scientific Journal of Tra Vinh University 1, no. 35 (January 8, 2020): 51–61. http://dx.doi.org/10.35382/18594816.1.35.2019.203.
Повний текст джерелаАнотація:
This study was conducted to determine the effectiveness of the design of reinforced concrete slabs of several civil engineering projects in Tra Cu district – Tra Vinh province. Utilizing the design documents of 6 projects, these slabs were redesigned based on TCVN 5574 – 2018. The design results were compared with those provided in the design documents. The results show that most of the design in the provided documents was either greater than or equal to the end design studied: the slab thickness is from 0% - 20%, the steel percentage of the slabs are from 0% - 63,3%, and the concrete quantity is from 0% - 20%. In conclusion, it is recommended for engineers to select an optimal slab design technique in order to reduce dead loads, to provide a reasonablesteel percentage and still being capable of carrying loads, which will result in an effective design for the project.
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Istomin, Andrey, and Maksim Kudryavtsev. "Strength of cast-in-place slabs for rectangular cross-section columns punching." E3S Web of Conferences 263 (2021): 02035. http://dx.doi.org/10.1051/e3sconf/202126302035.
Повний текст джерелаАнотація:
Flat slabs in contemporary buildings are most commonly supported by rectangular cross-section columns. Research of slabs supported by rectangular cross-section columns for punching is rather narrow. The purpose of this work was the experimental research of slabs punching by rectangular cross-section columns and adjustment of their design method. Reinforced concrete slabs 6 cm in thickness without transverse reinforcement were used as testing specimens. During tests load on the slab was transferred using stamps. Side ratios for stamps varied from 1 to 5 in experiments. Strength and strain properties of concrete were determined before slabs testing for punching. Ultimate loads, that resulted in slab punching, were acquired from test results. Formulae for punching load are suggested for rectangular cross-section columns punching based on obtained results. Generalized analysis of experimental research results shows that slab strength for punching is also influenced by short side of rectangular cross-section to slab thickness ratio.
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Nishizawa, Tatsuo, Yoshiki Murata, and Katsuro Kokubun. "Mechanical Behavior of Ultrathin Whitetopping Structure Under Stationary and Moving Loads." Transportation Research Record: Journal of the Transportation Research Board 1823, no. 1 (January 2003): 102–10. http://dx.doi.org/10.3141/1823-12.
Повний текст джерелаАнотація:
The structural design of ultrathin whitetopping (UTW) requires precise predictions of the loading stresses in the concrete slabs. A plate finite element model (FEM) is not used for structures with UTW because the model is not able to account for the asphalt subbase behaviors and the mechanical interaction between the concrete slab and asphalt subbase. A three-dimensional FEM (3DFEM) was used for the stress calculation of UTW. To take into account the mechanical interaction at the interface between the concrete slab and asphalt subbase as well as the load transfer across the joint, a general interface element was developed and incorporated into 3DFEM. Also, the viscosities of asphalt materials were considered by the viscoelastic formulation in the 3DFEM. A loading test was conducted on a test pavement. Stationary and moving loads were applied to the concrete slabs, and the strains in the slabs and the asphalt subbase were measured. By comparing the strains computed by 3DFEM with the measured strains, it was found that the viscosity of the asphalt subbase and the interface condition significantly affect the stresses in the concrete slab.
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Bakht, Baidar. "Revisiting arching in deck slabs." Canadian Journal of Civil Engineering 23, no. 4 (August 1, 1996): 973–81. http://dx.doi.org/10.1139/l96-902.
Повний текст джерелаАнотація:
The arching action in concrete deck slabs of girder bridges is generally recognized and is utilized by the Ontario Highway Bridge Design Code, and some other codes, to specify an empirical design method which leads to considerable savings in the amount of reinforcement. Despite this general recognition, there are some aspects of the arching action that are yet to be explored. To the knowledge of the author, all reported laboratory and field tests on deck slabs exploring its arching action under applied loads have been conducted by measuring strains in the bottom transverse reinforcement midway between the girders. Based on the results of tests on a full-scale model of a deck slab, it has been confirmed in this note that the transverse bottom reinforcement in the deck slab acts as a tie to the internal transverse arch in the slab. Because of embedment in concrete, the force in this reinforcement is the smallest midway between the girders, and not the largest as would be the case if the slab were in pure bending. Key words: arching in slabs, deck slabs, girder bridge, punching shear, steel-free deck slabs.
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Wang, Yifan, Tianlai Yu, Linlin Zhang, Lihui Yin, Yuxuan Wu, and Binglin Chen. "Fatigue Performance of Rib Beam Bridge Slabs Reinforced with Polyurethane Concrete Based on the Damage Theory." Buildings 12, no. 6 (May 24, 2022): 704. http://dx.doi.org/10.3390/buildings12060704.
Повний текст джерелаАнотація:
In this paper, the rib beam bridge slabs were taken as the research object. Static load and fatigue tests were carried out on the benchmark bridge slabs to determine the ultimate load capacity and fatigue life of the bridge slabs. Then, the bridge slab was pre-damaged and reinforced with polyurethane concrete. A fatigue test was carried out on the reinforced bridge slab to study the fatigue performance. Based on the damage theory, the fatigue damage reinforcement finite element models of the bridge slabs under different damage degrees were established. The fatigue performance of the reinforced bridge slabs was systematically studied. The results show that the fatigue damage of the reinforced bridge slab developed in stages. Compared to the unreinforced bridge slab, the fatigue damage of the reinforced bridge slab was significantly reduced at each stage. According to the least square method and numerical analysis results, a residual-bearing-capacity model including damage degree and fatigue cycles of the reinforced bridge slabs is proposed, which can be used as a reference in bridge slab reinforcement design.
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Luo, Dan, and Li Zhe Luo. "Study and Engineering Practice on Cracks Control Measures for Concrete Face Slab of High CFRD." Advanced Materials Research 455-456 (January 2012): 1606–11. http://dx.doi.org/10.4028/www.scientific.net/amr.455-456.1606.
Повний текст джерелаАнотація:
Being the face slabs of high concrete faced rockfill dams (CFRD) are under complex stress state, the slabs are relative vulnerable. And crack is easy to form on slab, which can influence durability and integrity, then weaken impermeable ability and safety of dam. The factors that contribute to the structural cracks, non-structural cracks and extruding cracks of concrete face-slab are analyzed in detail. The result shows that the structural crack is mainly due to differential settlement, the extruding crack in riverbed position is mainly caused by rockfill body over-settlement of dam beyond 150m high and the non-structural crack is mainly caused by temperature shrinkage and air shrinkage. Therefore, crack control of CFRD face slab should be regulated by the three means coming from structural design, construction control and concrete material. It is proved by the practices in Shuibuya CFRD that face slab cracks on CFRD beyond 200m high can be reduced effectually by the present technique means.
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Aman, Syafiqah Shahrul, Bashar S. Mohammed, Mubarak Abdul Wahab, and Abdullah Anwar. "Performance of Reinforced Concrete Slab with Opening Strengthened Using CFRP." Fibers 8, no. 4 (April 21, 2020): 25. http://dx.doi.org/10.3390/fib8040025.
Повний текст джерелаАнотація:
Openings in reinforced concrete (RC) slabs are not commonly prescribed in design codes. Even when they are, they raise concerns regards to the size of the openings and the location of the applied loads. Lack of sufficient information about the load-carrying capacity of the slabs with openings and performance is another concern. Hence, this research addresses the structural behavior of slabs with openings coated with Carbon Fiber Reinforced Polymer (CFRP) sheet. In the experimental part, ten slabs were cast with a dimension of 1000 mm × 530 mm × 25 mm, among which nine slabs had openings and one slab was without opening (control slab). The configuration of the CFRP sheet includes coating in the form of single, double, and triple layers. Experimental results show that the slab with a triple coating of the CFRP layer offers the maximum resistance towards the loading rate. Moreover, with the increase in CFRP layers, the value of deflection is minimized.
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Wei, Liu, and T. F. Fwa. "Closed-Form, Six-Slab, Thick-Plate Solution for Analysis of Edge Slab of Concrete Pavement." Transportation Research Record: Journal of the Transportation Research Board 1919, no. 1 (January 2005): 2–15. http://dx.doi.org/10.1177/0361198105191900101.
Повний текст джерелаАнотація:
The development and application of a theoretical closed-form solution of a six-slab, thick-plate model for the structural design and analysis of an edge slab in jointed concrete pavement subjected to vertical loads are described. The jointed concrete pavement system is idealized as a six-slab system resting on a Winkler foundation. The six slabs are arranged in two rows with three slabs in each row. The loaded slab of interest is represented by a middle slab with five surrounding slabs to consider the effects of jointed pavement system. Fundamental equations of the proposed model were derived from thick-plate theory. Solutions of the fundamental equations were obtained by superposition of the solutions of appropriate elemental slabs. The validity of the proposed solutions was checked against finite element solutions. The six-slab model was applied to analyze the critical stresses and deflections of an edge slab under the following three loading conditions: interior, edge, and corner loadings. Comparisons of the computed critical stresses and deflections were made with Westergaard's solutions. Westergaard's solutions were found to overestimate the maximum bending stresses and deflections for large slabs but to tend to underestimate these pavement responses for small slabs. The likelihood of underestimation by Westergaard's solutions also increased as the load transfer efficiency of pavement joints fell.
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Bartók, Andrej. "Design of Concrete Slabs Reinforcement – Methods of FEM Results Interpretation Incorporating Twisting Moments." Key Engineering Materials 691 (May 2016): 388–97. http://dx.doi.org/10.4028/www.scientific.net/kem.691.388.
Повний текст джерелаАнотація:
There are many analytical methods to solve internal forces of slabs. But structural engineers work with structural analysis software, based mainly of finite element method (FEM). Interpretation of that analysis results may lead to errors during concrete slab reinforcement design. There are some methods to solve the problem. Most familiar are Wood-Armer equations, introduced in 1968. But other methods exists furthermore. It is common, that design engineer doesn’t know, which method his program uses. This article deals with common – not only Wood-Armer - methods of concrete slab reinforcement design incorporating twisting moments, design of skew angle reinforcement etc. Description of selected software approach.
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Tošić, Nikola, and Jean Torrenti. "New Eurocode 2 provisions for recycled aggregate concrete and their implications for the design of one-way slabs." Gradjevinski materijali i konstrukcije 64, no. 2 (2021): 119–25. http://dx.doi.org/10.5937/grmk2102119t.
Повний текст джерелаАнотація:
A significant amount of research has been performed on recycled aggregate concrete (RAC), both on the material and structural level. This has enabled the formulation of material and structural resistance models that can be safely and reliably used for the structural design of RAC members and the new Eurocode 2 (EC2) will contain an informative annex detailing provisions for the design of RAC. Thus, an increased market uptake of recycled aggregate (RA) can be achieved, leading to potential sustainability improvements of concrete structures. In order to familiarize designers with the new provisions for RAC, this paper presents an example of one-way slab design using varying RA substitution ratios, as well as a parametric study on the implications of RAC provisions on slab slenderness. The results of this study show that RAC one way slabs can be successfully designed using EC2. Although such slabs might require larger depths than natural aggregate concrete slabs, their applicability in the typical slenderness range is possible.
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Madan, Chinnasamy Samy, Swetha Munuswamy, Philip Saratha Joanna, Beulah Gnana Ananthi Gurupatham, and Krishanu Roy. "Comparison of the Flexural Behavior of High-Volume Fly AshBased Concrete Slab Reinforced with GFRP Bars and Steel Bars." Journal of Composites Science 6, no. 6 (May 26, 2022): 157. http://dx.doi.org/10.3390/jcs6060157.
Повний текст джерелаАнотація:
Fiber-reinforced polymer (FRP) rods are advanced composite materials with high strength, light weight, non-corrosive properties, and superior durability properties. Under severe environmental conditions, for concrete structures, the use of glass-fiber-reinforced polymer (GFRP) rods is a cost-effective alternative to traditional steel reinforcement. This study compared the flexural behavior of an OPC concrete slab with a high-volume fly ash (HVFA) concrete slab reinforced with GFRP rods/steel rods. In the fly ash concrete slabs, 60% of the cement used for casting the slab elements was replaced with class F fly ash, which is emerging as an eco-friendly and inexpensive replacement for ordinary Portland cement (OPC). The data presented include the crack pattern, load–deflection behavior, load–strain behavior, moment–curvature behavior, and ductility of the slab specimens. Additionally, good agreement was obtained between the experimental and nonlinear finite element analysis results using ANSYS 2022-R1. The study also compared the experimental moment capacity with the most commonly used design standard ACI 440.1R-15. This investigation reveals that there is a huge potential for the utilization of GFRP rods as reinforcement in fly ash concrete slabs.
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Marcalikova, Zuzana, Vlastimil Bilek, Oldrich Sucharda, and Radim Cajka. "Analysis of Fiber-Reinforced Concrete Slabs under Centric and Eccentric Load." Materials 14, no. 23 (November 24, 2021): 7152. http://dx.doi.org/10.3390/ma14237152.
Повний текст джерелаАнотація:
Research on the interaction between slabs and subsoil involves the field of materials engineering, concrete structures, and geotechnics. In the vast majority of cases, research focuses on only one of these areas, whereas for advanced study and computer simulations, detailed knowledge of the whole task is required. Among the new knowledge and information upon which this article focuses is the evaluation of subsoil stress using specialized pressure cells, along with detailed measurements of the deformation of a fiber-reinforced concrete slab. From a design point of view, this research is focused on the issue of the center of the cross section and the influence of eccentricity. Knowledge in this area is not yet comprehensively available for fiber-reinforced concrete slabs, where 2D deformation sections of the slab and 3D deformation surfaces of the slab are used in experiments. The experimental program includes a centrically and eccentrically loaded slab. These are structural elements that were tested on a specialized device. Both slabs had the same concrete recipe, with a dispersed reinforcement content of 25 kg/m3. The dimensions of the slab were 2000 × 2000 × 150 mm. Laboratory tests assessed compressive strength, the modulus of elasticity, splitting tensile strength, and bending tensile strength. Based on approximate data from the 3D deformation surfaces, an evaluation of the load-displacement diagrams for the center of the slab and for the center of eccentricity was performed. In conclusion, an overall evaluation and discussion of the results relies on experiments and the mechanical properties of fiber-reinforced concrete.
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Laco, Kamil, and Viktor Borzovič. "Reliability of Approach Slabs and Modelling of Transition Zones of Bridges." Applied Mechanics and Materials 821 (January 2016): 741–46. http://dx.doi.org/10.4028/www.scientific.net/amm.821.741.
Повний текст джерелаАнотація:
The approach slab is the structural member of transition zones, which compensates a different settlement of bridge abutment and a road embankment. The main reason of different settlement is the consolidation of soil under the slab and the abutment. The geometry of approach slab, its length and the thickness is defined on the basis of differential settlement of embankment and the abutment. The static behaviour of slab is defined as a slab on elastic soil. The reinforced concrete slab is supported with the line rigid support on the one edge, and the rest of slab area interacts with the soil. The civil engineers design the reinforcement in those slabs based on the simplified structural scheme, without considering the elastic area support. This scheme is the simple supported slab on the both ends. The paper is dealing with the comparing of different structural models of the reinforced concrete approach slabs. The complex models of transition zones with the brick elements of the soil and the interaction with the reinforced concrete slab with the soil embankment are compared with the simplified models used by civil engineers. The analysis was performed on the transition zone of highway bridge from Slovakia based on its geometry and the subsoil consistence. In the parametric study was compared 8 soil stiffness’s on 10 structural models.
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Holomek, Josef, Miroslav Bajer, Jan Barnat, and Martin Vild. "Composite Slabs with Prepressed Embossments – Longitudinal Shear Resistance." Applied Mechanics and Materials 769 (June 2015): 289–93. http://dx.doi.org/10.4028/www.scientific.net/amm.769.289.
Повний текст джерелаАнотація:
Composite slabs with prepressed embossments present an effective solution for horizontal structures. Prepressed embossments ensure composite action after hardening of concrete. Longitudinal shear failure mode typically governs if the shear resistance of embossments is not sufficient for full composite action. Mutual separation of thin-walled sheeting from concrete and its deformation inside the rib is characteristic for this failure mode. Design methods for composite slabs use full scale bending tests in several series to determine their bearing capacity. A less expensive alternative is to use small-scale shear tests to determine shear characteristics of the sheeting. This paper presents detailed numerical models of slab in shear and models of slab in bending with and without embossments. These models are compared with previously performed experiments. Key WordsComposite slab; steel sheeting; concrete; prepressed embossment; longitudinal shear; experiment; numerical model
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Wu, Lili, Lipei An, and Jiawei Li. "Shear Capacity of Open Sandwich Steel Plate-Concrete Composite Slab: Experimental and Analytical Studies." Advances in Civil Engineering 2019 (July 10, 2019): 1–14. http://dx.doi.org/10.1155/2019/4726538.
Повний текст джерелаАнотація:
Considering that the fixed crack model by default of the general finite element software was unable to simulate the shear softening behavior of concrete in the actual situation, a rotational crack model based on the modified compression field theory developed by UMAT (user material) of ABAQUS software was proposed and applied to the nonlinear analysis, and a numerical simulated model for the steel-concrete composite slab was built for shear analysis. Experimental studies and numerical analyses were used to investigate the shear load-carrying capacity, deformation, and crack development in steel plate-concrete composite slab, as well as the effects of the shear span ratio and shear stud spacing on the shear performance and the contribution of the steel plate and the concrete to the shear performance. Shear capacity tests were conducted on three open sandwich steel plate-concrete composite slabs and one plain concrete slab without a steel plate. The results indicated that the shear-compression failure mode occurred primarily in the steel plate-concrete composite slab and that the steel plate sustained more than 50% of the total shear force. Because of the combination effect of steel plate, the actual shear force sustained by the concrete in the composite slab was 1.27 to 2.22 times greater than that of the calculated value through the Chinese Design Code for Concrete Structures (GB 50010-2010). Furthermore, the shear capacity of the specimen increases by 37% as the shear stud spacing decreases from 250 mm to 150 mm. By comparing the shear capacity, the overall process of load deformation development, and the failure mode, it was shown that the simulation results corresponded with the experimental results. Furthermore, the numerical simulation model was applied to analyze the influence of some factors on composite slab, and a formula of shear bearing capacity of slab was obtained. The results of the formula agreed with the test result, which could provide references to the design and application of steel plate-concrete composite slab.
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Zhang, Qing, Graeme J. Milligan, and Maria Anna Polak. "Nonlinear finite element analysis of punching shear strength of reinforced concrete slabs supported on L-shaped columns." Budownictwo i Architektura 19, no. 4 (November 2, 2020): 125–38. http://dx.doi.org/10.35784/bud-arch.2122.
Повний текст джерелаАнотація:
Most current concrete design codes include provisions for punching shear of reinforced concrete slabs supported on columns with L, T, and cruciform shapes. Reference studies verifying the accuracy of these code provisions are typically not provided. Empirical data of punching failures of slabs supported on columns with L, T, and cruciform shapes are limited due to the cost and time required to test specimens with slab thicknesses and column sizes commonly used in practice. In this paper, the punching shear behaviour of five interior L-shaped slab-column connections, one without a slab opening and four with slab openings, subjected to static concentric loading are analyzed using a plasticity-based nonlinear finite element model (FEM) in ABAQUS. The FEM is similar to models previously calibrated at the University of Waterloo and are calibrated considering nine slabs that are tested to study the impact of column rectangularity on the punching shear behaviour of reinforced concrete slabs. The finite element analysis results indicate that shear stresses primarily concentrate around the ends of the L, and that current code predictions from ACI 318-19 and Eurocode 2 may be unconservative due to the assumed critical perimeters around L-shaped columns.
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Ahmed, Saddam M., Gunasekaran Umarani, and Gregory A. MacRae. "A Parametric Study of the Reinforced Concrete Slab Subjected to Dynamic Excitation." Applied Mechanics and Materials 147 (December 2011): 270–77. http://dx.doi.org/10.4028/www.scientific.net/amm.147.270.
Повний текст джерелаАнотація:
The width of effective slab to estimate the beam flexural strength at the beam ends in structures subjected to lateral loading, such as earthquake, is not explicitly addressed in design codes. As a result, designers often ignore the contribution of floor slabs to the lateral load resistance. There is a need for a simple model to assess the slab contribution to beam strength for analysis and design. General expressions for the yield loading and stiffness characteristic of the slab element have been developed which is more sensitively depend on yield line theory beside other parameters such as spacing, yield strength, area of reinforcement, and the span length. A model considering beam growth, bending effects and the slab effect is being considered in the present work. The results of the analytical investigation are compared with experimental results. The slab element model is then used to conduct a parametric study aiming to investigate the effect of the distribution and strength of the slab steel. It is shown that the performance of the unit is directly related to this steel.