Journal articles: 'Short-term deflection'

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Du, Jin Sheng, and Hai Bin Liu. "Effect of Pier Vertical Deformations on Deflections of Main Girders for High Pier and Long-Span Continuous Rigid-Frame Bridges." Advanced Materials Research 163-167 (December 2010): 1436–39. http://dx.doi.org/10.4028/www.scientific.net/amr.163-167.1436.

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In some long-span prestressed concrete box girder bridges, excessive deflections of main girders are often observed. These unacceptable deflections have detrimental influence on the serviceability and safety of the structures. To better understand and estimate short term and long term deflections for prestressed concrete box girder bridges, pier vertical deformation and its effect on deflections of main girders of Jinghe Bridg is investigated in this paper. Piers in Jinghe Bridge are tall and the difference in height between piers up to 22 m. Analysis indicates that although the short term deformations of piers are small, the long term deformations of piers can be 3 times as large as that of short-term ones. The maximum short-term downward deflection of Jinghe Bridge caused by pier deformation for main girders is 7.7 mm and the maximum long-term downward deflection is 33.3 mm. These values are relatively small compared with the span length of the bridge. But when the deflection of the main girder itself is also included, the final total deflection of the main girder may exceed the design code limit.

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Zhang, Lei, and Jin Tian. "Short- and Long-Term Deflection of Concrete Structures." Advanced Materials Research 690-693 (May 2013): 714–19. http://dx.doi.org/10.4028/www.scientific.net/amr.690-693.714.

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The general concepts of two basic forms of deflection are summarized and the existing calculation theories of deflection are introduced; two cases of concrete structure deflection, which are short-and long-term deflection, are discussed through comparison. Further, the basic theories of deflection calculation and deflection control methods are indicated based on two different cases in this paper.

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Ghali, Amin, Mamdouh Elbadry, and Sami Megally. "Two-year deflections of the Confederation Bridge." Canadian Journal of Civil Engineering 27, no. 6 (December 1, 2000): 1139–49. http://dx.doi.org/10.1139/l00-050.

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A comprehensive research program is currently in progress to monitor and study the behavior and performance of the Confederation Bridge. Part of this program is on monitoring short- and long-term deflections to evaluate the deflection prediction techniques employed in the design of concrete structures in general and this bridge in particular. The investigation comprises measurements of parameters related to the materials used in the bridge. This paper presents some field measurements of vertical deflection as well as the results of computer analysis. Short-term deflections are measured at the time of installation of precast units and also in truck-loading tests. After completion of construction, the deflections are measured at specified intervals. The last readings reported in this paper have been taken 27 months after completion of construction. The computer program CPF (Cracked Plane Frames in prestressed concrete) is employed for analysis of the monitored part of the Confederation Bridge. The bridge is modeled as a plane frame in which the nonprestressed and prestressed steels are considered. Several analyses are performed employing the actual time-dependent concrete properties measured in the field and those calculated from the ACI Committee 209 equations and CEB-FIP Model Code. Comparisons are made between the measured and the predicted deflections. The predicted deflections are found to be in close agreement with the measured values, which indicates that the deflection prediction techniques used in design of this bridge are adequate.Key words: computer analysis, concrete bridges, Confederation Bridge, creep, deflections, field measurements, long-term, prestressed steel, segmental construction, short-term, shrinkage, time-dependent.

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El-Zeadani, Mohamed, Raizal Saifulnaz Muhammad Rashid, Mugahed Yahya Hussein Amran, Farzad Hejazi, and Mohd Saleh Jaafar. "Short-term deflection of RC beams using a discrete rotation approach." International Journal of Advanced Structural Engineering 11, no. 4 (October 22, 2019): 473–90. http://dx.doi.org/10.1007/s40091-019-00247-5.

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Abstract Quantifying the deflection of RC beams has been performed traditionally using full-interaction moment–curvature methods without considering the slip that takes place between the reinforcement and the surrounding concrete. This was commonly carried out by deriving empirically based flexural rigidities and using elastic deflection equations to predict the deformation of RC structures. However, as flexural and flexural/shear cracks form in RC beams with increase in applied load, the reinforcement steel begins to slip against the surrounding concrete surface causing the cracks to widen and ultimately increasing the deflection at mid-span. Current design rules cannot cope directly with the deformation induced by the widening of cracks. Because of that, this study focused on predicting the non-time dependent deflection of RC beams at both service and ultimate limit states using a mechanics-based discrete rotation approach. The mechanics-based solution was compared with experimental test results and well-established code methods to which a good agreement between the results was observed. The method presented accounts for the non-linear behavior of the concrete in compression, the partial-interaction behavior of the reinforcement, and the deflection was computed while considering the rotation of discrete cracks. Due to its generic nature, the method presented does not require any calibration with experimental findings on the member level, which makes it appropriate to quantify the deflection or RC structures with different types of concrete and novel reinforcement material.

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Visintin, P., D. J. Oehlers, R. Muhamad, and C. Wu. "Partial-interaction short term serviceability deflection of RC beams." Engineering Structures 56 (November 2013): 993–1006. http://dx.doi.org/10.1016/j.engstruct.2013.06.021.

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Zhuravskyi, Oleksandr, and Dmytro Smorkalov. "Investigation of single- and double-layer slabs supported on four sides." USEFUL online journal 2, no. 4 (December 29, 2018): 44–55. http://dx.doi.org/10.32557/useful-2-4-2018-0005.

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Presented method and results of experimental research of deflection of single-layer and two-layer slabs influenced by short-term lateral load. Proposed method of calculation based on the limit equilibrium method, calculation of slab deflections values by LIRA-CAD bundled software. The comparison of experimental and theoretical results of the calculation of deflections slabs.

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Duy Nguyen, Phan, Vu Hiep Dang, Ngoc Anh Vu, and Polikutin Aleksei Eduardovich. "Long-term Deflections of Hybrid GFRP/Steel Reinforced Concrete Beams under Sustained Loads." Civil Engineering Journal 6 (September 30, 2020): 1–11. http://dx.doi.org/10.28991/cej-2020-sp(emce)-01.

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One of the solutions to improve the flexural behavior of Glass fiber reinforced polymer (GFRP) reinforced concrete (RC) beams is the addition of tensile longitudinal steel reinforcement. The numerous studies to date on hybrid GFRP/steel RC elements have mainly focused on the static and short-term responses, very little work has been done regarding the long-term performance. This paper presents experimental results of time-dependent deflections of cracked GFRP and hybrid GFRP/steel RC beams during a 330-day-period in natural climate conditions. Three hybrid GFRP/steel and one GFRP RC beams with dimensions 100×200×2000 mm were tested in four-point bending. Different steel reinforcement ratios were used to evaluate the effect of the steel reinforcement on the long-term behavior of the beams. Experimental results show that the immediate deflections are inversely proportional to the additional steel reinforcement. With the same initial instantaneous deflection, the total deflection increases when increasing the steel reinforcement ratio. Also, temperature (T) and relative humidity (RH) significantly affect the long-term deflection of the tested beams. The measured long-term deflections were found to be in good agreement with the theoretical values calculated from the proposed method. However, there was an overestimation when using ACI 440.1R-15 or CSA-S806-12 procedures.

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Sherif, Alaa G., and Walter H. Dilger. "Critical review of CSA A23.3-94 deflection prediction for normal and high strength concrete beams." Canadian Journal of Civil Engineering 25, no. 3 (June 1, 1998): 474–89. http://dx.doi.org/10.1139/l97-106.

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The purpose of this paper is to critically review the provisions of CSA A23.3-94 for the deflection calculations of normal and high strength reinforced concrete beams. Comparison is made with the provisions of CEB-FIP MC 90 and EC 2 which is similar to the MC 90. Both short- and long-term deflections are discussed. Tests from the literature are used to assess the calculation methods suggested by the codes. These methods are the effective moment of inertia approach, the mean curvature approach, and the bilinear method. A parametric study is carried out to investigate the effect of the level of loading, shape of bending moment, and reinforcement ratio on the predicted deflections.Key words: code predictions, deflections, long term, reinforced concrete beams, short term.

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Liu, Jin Jun, and Tian Wen Wang. "Deflection Calculation on Reinforced Concrete Beams Strengthened by Externally Prestressing Transverse Tensioning Method." Advanced Materials Research 671-674 (March 2013): 430–36. http://dx.doi.org/10.4028/www.scientific.net/amr.671-674.430.

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Eight reinforced concrete beams (six externally reinforced and two contrast beams) were tested under primary or secondary load experiment. According to the test results, the existing specifications were applied to make calculations on short-term deflection which leaded to a large error. The secondary effect should be considered on calculating the deflection. Therefore, comparisons were made between the improved calculated value and test value on deflections of reinforced concrete beams strengthened by externally prestressed transverse tensioning method and they are in good agreement.

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Bai, Wen Hui. "Stiffness Revising to Recycled Course Aggregate Reinforced Concrete Beams under Short-Term Loading." Advanced Materials Research 168-170 (December 2010): 1443–48. http://dx.doi.org/10.4028/www.scientific.net/amr.168-170.1443.

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This paper mainly studies the deflection under short-term loading of recycled course aggregate reinforced concrete beam is calculated by using of the formula of short-dated rigidity in code for design of concrete structures. According to testing the flexural performance of 6 recycled course aggregate beams with the same section size, different replacement ratio of recycled coarse aggregate of 0%, 50%, 70%, 100% respectively and different percentage reinforcement of 0.68%, 0.89%, 1.13% respectively, analyzes relation between deflection and replacement ratio of recycled coarse aggregate, deflection and percentage reinforcement, compare measured value and calculated value using of current codes and make statistical analysis this data . By regressing and analyzing the experimental data from literature, supplied short-dated rigidity modified formula of recycled course aggregate beam. The calculation results are in good agreement with the experimental data. The formula of short-dated rigidity can accurately calculate deflection under short-term loading of recycled course aggregate reinforced concrete beam, and can be referenced in engineering practice and correlative regulations.

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Sarkar, Pradip, Maidhily Govind, and Devdas Menon. "Estimation of short-term deflection in two-way RC slab." Structural Engineering and Mechanics 31, no. 2 (January 30, 2009): 237–40. http://dx.doi.org/10.12989/sem.2009.31.2.237.

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SARKISOV, Dmitry Yu, Georgy I. ODNOKOPYLOV, Vladimir V. KRYLOV, and Andriy O. ANNENKOV. "Numerical and experimental studies of deflections of conventional and strengthened reinforced concrete bendable elements under short-term dynamic loading." INCAS BULLETIN 13, S (August 3, 2021): 179–92. http://dx.doi.org/10.13111/2066-8201.2021.13.s.17.

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The relevance of this study is conditioned by the technical complexity of the design solutions for construction projects of ground-based space infrastructure. It is associated with the possibility of special loads in the form of an air shock wave in the event of a launch abort, a fall of a fragment, an emergency shutdown of engines, an air shock wave from the indirect impact of nuclear weapons, seismic loads, accidental cargo falls, terrorist attacks, etc. Such impacts with a high degree of probability lead to damage to building structures and in the future, they need to be reinforced. These building structures must have survivability under special loads and deform without collapsing. Under the dynamic loading, the energy intensity of the bendable structures is important, to determine which it is necessary to know the magnitude of the acting force and deflections. The effective load in a wide class of problems refers to the initial data, and the determination of reliable values of the dynamic deflection of the bendable structure is an actual problem. The purpose of this study is to conduct a numerical and experimental investigation of the deflection of conventional and strengthened reinforced concrete structures under short-term dynamic loading. This study used the following research methods: measurements of deflections and loads by strain measurement, graphical analytic research using Microsoft Excel, numerical calculation in the environment of the Explicit Dynamics module of the Ansys software package. As a result of the study, experimental investigation of conventional and strengthened bendable reinforced concrete elements under short-term dynamic loading was carried out, the values of the effective force and deflections were obtained. The same experiment was modelled in the environment of the Explicit Dynamics module of the Ansys software package. A comparison of the deflection parameters was made, based on the results of numerical and physical experiments on the example of a specific design, which showed satisfactory convergence.

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Birhane, Fiseha Nega, Sung-Il Kim, and Seung Yup Jang. "Long-Term Deflection of Prestressed Concrete Bridge Considering Nonuniform Shrinkage and Crack Propagation by Equivalent Load Approach." Applied Sciences 10, no. 21 (November 2, 2020): 7754. http://dx.doi.org/10.3390/app10217754.

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Long-span prestressed concrete (PSC) bridges often suffer excessive deflection during their service lives. The nonuniform shrinkage strains of concrete caused by uneven moisture distributions can induce significant additional deflections, when combined with the creep and cracking of the concrete. Current design practices usually overlook these factors, and the few proposed approaches to consider them are complex and computationally expensive. This study proposes a simplified approach for considering the effect of nonuniform shrinkage by using the equivalent load concept in combination with a nonlinear analysis of the creep and cracking using three-dimensional finite element models. The long-term deflections of short-, medium-, and long-span PSC bridges are calculated under the combined effects of creep, shrinkage, and cracking. The results show that the nonuniform shrinkage effect is significant in medium- to long-span bridges, and that the cracking of the concrete reduces the stiffness, thereby increasing the long-term deflection of the bridges (more severely so in combination with creep and shrinkage). The predicted long-term deflections reasonably agree with the measured data. Thus, the equivalent load approach is effective for calculating long-term deflections considering nonuniform shrinkage strains, without the complicated and expensive coupling of moisture transport and structural analyses.

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Tian, Pan-Pan, Hong-Xing Qiu, Zhou-Zhou Liang, and Jian Sun. "Reliability-based assessment of flexural timber components with ultimate deflection performance." Advances in Structural Engineering 23, no. 16 (July 14, 2020): 3469–80. http://dx.doi.org/10.1177/1369433220940146.

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Assessing the deflection performance of existing flexural timber components is of paramount importance for making better, reliable, and substantiated decisions. The main purpose of this article is to propose four-level reliability index β and deflection criteria for updating existing flexural timber components (main beam, joist, purlin, and rafter) based on long-term deflection probabilistic model, limit state functions, and load combinations. The long-term deflection probabilistic model was obtained through creep deflection and short-term deflection model. Limit state functions were considered to be ultimate limit states of load-bearing capacity. In addition, four-level reliability index β were calculated by three live loads (residential live load, office live load, and snow live load) and seven load ratios ρ (0.2, 0.3, 0.5, 1.0, 2.0, 3.0, and 4.0). The results of proposed four-level criterion were illustrated with the reliable safety assessment for flexural timber components.

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15

Hu, Di, Lai Fa Wang, and Ji Ping Guo. "Calculation of Short-Term and Long-Term Behavior of Prestressed Concrete Box Girders Considering Effect of Shear Lag." Key Engineering Materials 400-402 (October 2008): 943–48. http://dx.doi.org/10.4028/www.scientific.net/kem.400-402.943.

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A set of formulae to calculate short-term behavior of simply supported prestressed concrete box girders under dead load and prestress are established based on energy method, in which shear lag and effect of prestressed steel and non-prestressed steel are taken into account. As the time-dependent relationship between stress and strain of concrete, equilibrium of sectional forces and compatibility equation are introduced, a novel approach to analyze long-term behavior of prestressed concrete box girders is presented, and the theoretical formulae considering the synthetic effect of creep and shrinkage of concrete, relaxation of prestressed steel, shear lag and restriction of steels are deduced, which can be used directly to calculate time-dependent deflection of box girder, stresses and strains of concrete and steel at any location at any time. Comparison of theoretical values shows that that the long-term deflection increases by shear lag while distribution of transverse concrete stresses become even by concrete creep and shrinkage.

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Liu, Xi, Yijia Sun, and Tao Wu. "Flexural Capacity and Deflection of Fiber-Reinforced Lightweight Aggregate Concrete Beams Reinforced with GFRP Bars." Sensors 19, no. 4 (February 20, 2019): 873. http://dx.doi.org/10.3390/s19040873.

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Adding fibers is highly effective to enhance the deflection and ductility of fiber-reinforced polymer (FRP)-reinforced beams. In this study, the stress and strain conditions of FRP-reinforced lightweight aggregate concrete (LWC) beams with and without fibers at ultimate load level were specified. Based on the sectional analyses, alternative equations to predict the balanced reinforcement ratio and flexural capacity for beams failed by balanced failure and concrete crushing were established. A rational equation for estimating the short-term stiffness of FRP–LWC beams at service-load levels was suggested based on Zhu’s model. In addition, the contribution of the steel fibers on the short-term stiffness was quantified incorporating the effects of FRP reinforcement ratio. The proposed short-term stiffness model was validated with measured deflections from an experimental database for fiber-reinforced normal weight concrete (FNWC) beams reinforced with FRP bars. Furthermore, six glass fiber-reinforced polymer (GFRP)-reinforced LWC beams with and without steel fibers were tested under four-point bending. Based on the test results, the proposed models and procedures according to current design codes ACI 440.1R, ISIS-M03, GB 50608, and CSA S806 were linked together by comparing their predictions. The results showed that increasing the reinforcement ratio and adding steel fibers decreased the strain of the FRP bars. The flexural capacity of the LWC beams with and without steel fibers was generally underestimated by the design codes, while the proposed model provided accurate ultimate moment predictions. Moreover, the proposed short-term stiffness model yielded reasonable estimations of deflection for both steel fiber-reinforced lightweight aggregate concrete (SFLWC) and FNWC beams.

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Sinha, Nirmal K., and Baolin Cai. "Elasto-Delayed-Elastic simulation of short-term deflection of fresh-water ice covers." Cold Regions Science and Technology 24, no. 2 (May 1996): 221–35. http://dx.doi.org/10.1016/0165-232x(95)00004-u.

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Frid, Semen, Sophia Kiseleva, Natalya Lisitskaya, and Alexander Mordinsky. "Approaches for short-term photovoltaic energy production forecast in Russian climate conditions." E3S Web of Conferences 216 (2020): 01018. http://dx.doi.org/10.1051/e3sconf/202021601018.

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Different techniques for short-term energy production by photovoltaic solar parks (PVSP) were considered taking into account specific features of Russian energy market. Based on theoretical simulation using numerical weather prediction results and experimental data it has been shown, that even for low precision techniques their application allows to improve economics of PVSP’s operation. With a decrease in the forecast error by 1.5–2 times, the economic losses due to the grid dispatch schedule deflection decrease by 5–9 times.

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Oad, M., A. H. Buller, B. A. Memon, and N. A. Memon. "Impact of Long-Term Loading on Reinforced Concrete Beams Made with Partial Replacement of Coarse Aggregates with Recycled Aggregates from Old Concrete." Engineering, Technology & Applied Science Research 9, no. 1 (February 16, 2019): 3818–21. http://dx.doi.org/10.48084/etasr.2498.

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This research work presents an experimental evaluation of the effect of sustained loading on reinforced concrete beams made with 50% replacement of natural coarse aggregates with aggregates from old concrete. A total of 9 RC beams were cast, 6 with natural coarse aggregates and 3 with recycled concrete aggregates. All beams were cured for 28 days in standard fashion. Among the first batch, 3 beams were used to test under short term loading till failure. An application of 50% of short-term loading followed on all beams assembled on purpose made frames. All beams were monitored for deflection, strain, and cracking. Both deflection and strain remained within limits. Crack monitoring revealed maximum crack width 0.5 mm. After six months of sustained load, beams were removed from the frames and tested in universal load testing machine with central point load till failure. The load-deflection pattern of all beams was observed to be almost similar and 22.12% higher in recycled concrete beams than all-natural aggregate beams. The results show promising use of recycled concrete aggregates in new concrete subjected to sustained loading.

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JUNGES, E., and H. L. LA ROVERE. "Comparison between simplified and FE models for short-term deflection in continuous RC beams." Revista IBRACON de Estruturas e Materiais 10, no. 2 (April 2017): 415–50. http://dx.doi.org/10.1590/s1983-41952017000200007.

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Abstract In this work, a comparative study of different simplified methods and nonlinear finite element (FE) models used for calculating short-term deflections (vertical displacements of the longitudinal axis) in continuous reinforced concrete (RC) beams, under service loads, is performed. The simplified methods employed are the one proposed by Branson and the bilinear method recommended by the European Code CEB - Design Manual on Cracking and Deformations. Two finite element models are utilized: the first one with frame elements in which material nonlinearities are considered along the element and its cross section divided into layers, by using of constitutive relationships for steel and concrete, while the second one utilizes beam elements, with physical nonlinearity considered by means of moment-curvature diagrams, obtained from Branson equation. Several examples of continuous RC beams under service loads are analysed and the results obtained by the different models are compared taking as reference the nonlinear frame element model. A few conclusions and recommendations regarding the use of the different methods are drawn at the end of the work.

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El-Zeadani, Mohamed, M. R. Raizal Saifulnaz, F. Hejazi, Y. H. Mugahed Amran, M. S. Jaafar, Rayed Alyousef, and Fahed Alrshoudi. "Mechanics-based approach for predicting the short-term deflection of CFRP plated RC beams." Composite Structures 225 (October 2019): 111169. http://dx.doi.org/10.1016/j.compstruct.2019.111169.

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Guo, Aiping, Ajuan Jiang, Jie Lin, and Xiaoxiao Li. "Data mining algorithms for bridge health monitoring: Kohonen clustering and LSTM prediction approaches." Journal of Supercomputing 76, no. 2 (October 29, 2019): 932–47. http://dx.doi.org/10.1007/s11227-019-03045-8.

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Abstract In recent years, bridge health monitoring system has been widely used to deal with massive data produced with the continuous growth of monitoring time. However, how to effectively use these data to comprehensively analyze the state of a bridge and provide early warning of bridge structure changes is an important topic in bridge engineering research. This paper utilizes two algorithms to deal with the massive data, namely Kohonen neural network and long short-term memory (LSTM) neural network. The main contribution of this study is using the two algorithms for health state evaluation of bridges. The Kohonen clustering method is shown to be effective for getting classification pattern in normal operating condition and is straightforward for outliers detection. In addition, the LSTM prediction method has an excellent prediction capability which can be used to predict the future deflection values with good accuracy and mean square error. The predicted deflections agree with the true deflections, which indicate that the LSTM method can be utilized to obtain the deflection value of structure. What’s more, we can observe the changing trend of bridge structure by comparing the predicted value with its limit value under normal operation.

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Krizma, Martin, Lubomir Bolha, Martin Moravcik, and Matus Holubek. "Influence of Contact of Damaged Reinforced Concrete Beam and Strengthening Slab for Deformation and Resistance of Reinforced Element in the Long-Term Loading." Key Engineering Materials 738 (June 2017): 164–74. http://dx.doi.org/10.4028/www.scientific.net/kem.738.164.

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Experimental and theoretical research oriented on the influence of the time factor to limit states of damaged and then reinforced beams by the strengthening slab. In experiments there were performed two types of contact - reinforced contact (beams ST) "damaged beam / strengthening slab", respectively unreinforced contact with geometric indented modification (beams Z). Both types are based on rules EC2 for short-term load. The results are compared with short-term tests of both types of contact. In long-term studies, we have used as comparative values results for unreinforced beams (beams LTL-n). In both cases the creep coefficients are set for the following variables - total deflection a (tot), and the deflections a (sh) of shear, and the a (fl) the bending moment, the shear deformation γ, curvature ρ. All tests were carried out at the level of loading γ = 0.50. The determining of the creep coefficients was based on the experimental deformation of the fictitious truss system, which have been processed by Williot-Mohr translocation patterns. The results form the input values for the experimental elements in repetitive loading at the same level load.

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Xu, Yun, Yin Xu, Jin Tang Cai, and Hong Guang Luo. "Experimental Study on Short-Term Rigidity for Reinforced Concrete Beams Strengthened with CFRP Board." Advanced Materials Research 163-167 (December 2010): 3421–28. http://dx.doi.org/10.4028/www.scientific.net/amr.163-167.3421.

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The experimental study and finite element analysis of RC beams strengthened with CFRP board are introduced in this essay. Test research of six beams stuck with CFRP board on their tension faces has been carried out on rigidity by contrasting with three nonstrengthened beams. Three specimens are primary loading beams and the others are secondary loading beams, the calculating formula for the short-term rigidity on the section of concrete beams strengthened with CFRP board has been established. Calculation is carried out on short-term deflection of RC beams strengthened with CFRP board subjected to primary load and secondary load. The results indicate that the RC structure can be strengthened effectively by sticking with CFRP board, so that the expansion of crack and rigidity of beam can be controlled especially, and the experimental results compared with those predicted by the formula in resemblance.

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Zhao, Huajing, Wei Liu, Hao Guan, and Chunqing Fu. "Analysis of Diaphragm Wall Deflection Induced by Excavation Based on Machine Learning." Mathematical Problems in Engineering 2021 (February 11, 2021): 1–10. http://dx.doi.org/10.1155/2021/6664409.

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For the concrete diaphragm wall (CDW) supported excavation, excessive wall deflection may pose a potential risk to adjacent structures and utilities in urban areas. Therefore, it is of significance to predict the CDW deformation with high accuracy and efficiency. This paper investigates three machine learning algorithms, namely, back-propagation neural network (BPNN), long short-term memory (LSTM), and gated recurrent unit (GRU), to predict the excavation-induced CDW deflection. A database of field measurement collected from an excavation project in Suzhou, China, is used to verify the proposed models. The results show that GRU exhibits lower prediction errors and better robustness in 10-fold cross validation than BPNN and executes less computational time than LSTM. Therefore, GRU is the most suitable algorithm for CDW deflection prediction considering both effectiveness and efficiency, and the predicted results can provide reasonable assistance for safety monitoring and early warning strategies conducted on the construction site.

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Sadowska-Buraczewska, Barbara, and Małgorzata Grzegorczyk-Frańczak. "Sustainable Recycling of High-Strength Concrete as an Alternative to Natural Aggregates in Building Structures." Sustainability 13, no. 8 (April 12, 2021): 4286. http://dx.doi.org/10.3390/su13084286.

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The application of recycled coarse aggregates (RCA) in high-performance concrete (HPC) was analyzed in the article. In the paper, the behavior of HPC with coarse recycled aggregate and natural coarse aggregate (NCA) was compared. Short-term experiments were conducted, including concrete deformation, deflection, load bearing capacity, and cracking of beams. The analysis involved reinforced concrete T-beams made in 100% of RCA or NCA. The studies indicated that the beams with recycled aggregate are characterized by greater deflection and 7.6% lower load bearing capacity in comparison to the beams with NCA. Substitution of coarse natural aggregate with RCA reduced the compressive and tensile strengths by 20 and 26 (%), whereas and the modulus of elasticity was decreased by 15%.

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Wang, Lei, Jin Yi, Jiwang Zhang, Wu Chen, and Feng Fu. "Short-Term Flexural Stiffness Prediction of CFRP Bars Reinforced Coral Concrete Beams." Materials 14, no. 2 (January 19, 2021): 467. http://dx.doi.org/10.3390/ma14020467.

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FRP (Fiber Reinforced Polymer) Bar reinforced coral concrete beam is a new type of structural member that has been used more and more widely in marine engineering in recent years. In order to study and predict the flexural performance of CFRP reinforced coral concrete beams, the flexural rigidity, crack morphology and failure mode of concrete were studied in detail. The results show that under the condition of similar reinforcement ratio, the flexural rigidity of CFRP reinforced coral concrete beam is significantly lower than that of ordinary reinforced concrete beam. Increasing the cross-section reinforcement ratio within a certain range can increase the bending stiffness of the test beam or reduce the deflection, but the strength utilization rate of CFRP reinforcement is greatly reduced. The short-term bending stiffness of the CFRP reinforced coral concrete beam calculated by the existing standard formula is obviously higher. This paper proposes a modified formula for introducing the strain inhomogeneity coefficient (ψ) of CFRP bars and considers the relative slip between CFRP bars and coral concrete to predict the short-term flexural stiffness of coral concrete beams reinforced by CFRP bars. The formula was verified with the test results, and it was proved that the formula has a good consistency with the test results.

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Petkevičius, Mindaugas, and Juozas Valivonis. "ANALYSIS OF DEFLECTIONS UP TO FAILURE OF COMPOSITE STEEL FIBERREINFORCED CONCRETE SLABS." Engineering Structures and Technologies 2, no. 2 (June 30, 2010): 57–65. http://dx.doi.org/10.3846/skt.2010.08.

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Analysis of experimental and theoretical results of investigation into deflection of composite steel-concrete slabs is presented in the paper. Profiled steel sheeting (Holorib type) and steel fiber-reinforced concrete were used for specimens. For two slabs, the layer of concrete was reinforced with steel fiber, whereas the rest of them were not reinforced. Slabs were tested under static short-term load. The experimental investigation revealed that the use of steel fiber in composite slabs was effective. The meanings of deflections under the action of the bending moment M ≈0.6MR (where MR is the bending moment at failure of the slabs) were by 16–18% lower in the slabs with a steel fiber-reinforced concrete layer than in the slabs with a common concrete layer. The deflection of composite slabs directly depends on the rigidity of the shear bond between the profiled steel sheeting and the concrete layer. The method for the deflection analysis in composite slabs is based on the built-up bar theory. Influence of a cracked concrete layer on the deflection of the structure and plastic deformation in the compression zone of this layer are evaluated by this method. Furthermore, it evaluates the stiffness of separate layers and the stiffness of the shear bond between the profiled steel sheeting and the concrete layer. Experimental investigation was performed for determination of the shear characteristic for the bond between the steel sheeting and the concrete layer. Therefore, specimens were made of the same concrete mixture as that of the slabs. Theoretical analysis of deflection for the composite slabs was made. When the value of the bending moment is close to the service load M ≈0.6MR, agreement of the results of analysis with the experimental ones is sufficiently good. Ratio of the theoretical values to the experimental ones varies within the limits of ωobs / ωcall=1.01–1.03 for slabs with a usual concrete layer, and the ratio of ωobs/ ωcall=0.99–1.02 for slabs with a concrete layer reinforced with steel fiber.

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Sadowska-Buraczewska, Barbara, Danuta Barnat-Hunek, and Małgorzata Szafraniec. "Influence of Recycled High-Performance Aggregate on Deformation and Load-Carrying Capacity of Reinforced Concrete Beams." Materials 13, no. 1 (January 2, 2020): 186. http://dx.doi.org/10.3390/ma13010186.

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The use of recycled concrete aggregates (RCA) in high performance concrete (HPC) was analyzed. The paper presents the experimental studies of model reinforced concrete beams with a rectangular section using high-performance recycled aggregates. Two variable contents of recycled aggregate concrete were used in this study: 50% and 100%. The experimental analyses conducted as immediate studies concerned the following issues: short time loads-deflection, load-carrying capacity of beams, deformation of concrete, cracks, and long-term loads-deflection. The comparative analysis involves the behavior of beams made of high performance concrete-high strength concrete (HPC-HSC) recycled aggregates with model control elements made of regular concrete based on natural aggregates. The deflection values for the recycled aggregate beams were 20% higher than in the case of the control beams made of HPC-HSC exclusively. Replacement of aggregate with recycled concrete aggregate resulted in a large decrease in the value of these two parameters, i.e., compression strength by about 42% and modulus of elasticity by about 33%.

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Biscaia, Hugo, Noel Franco, Ricardo Nunes, and Carlos Chastre. "Old Suspended Timber Floors Flexurally-Strengthened with Different Structural Materials." Key Engineering Materials 713 (September 2016): 78–81. http://dx.doi.org/10.4028/www.scientific.net/kem.713.78.

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The design of timber beams has strict limits when it comes to the Serviceability Limit States (SLS) either in short-term or in long-term deflections. In order to face this aspect efficiently, the increase of the cross section of the beams might be considered as a solution. However, the prohibitive increase of the costs associated to this solution or the change of the initial architecture design of the building, opens the opportunity to find new and more efficient solutions. In that way, the use of additional reinforcements to the timber beams may be seen as a promising solution because either new or old structures would keep always their original aesthetical aspect with no significant self-weight increase and improving their behaviour to short and long-term actions. Therefore, the current study is dedicated to the analysis of composite timber beams where Fiber Reinforcement Polymers (FRP), steel or stainless steel are used to improve the stiffness, strength and deflection behaviour of old suspended timber floors. An experimental program was conducted where old suspended timber floors reinforced with CFRP strips were subjected to 4-point bending tests. A simplify nonlinear numerical model was developed to simulate the bending behaviour of the specimens and several other cases with other reinforcement configurations and different structural materials were assumed. The numerical analysis herein presented also takes into account both Ultimate and Serviceability Limit States of the reinforced specimens.

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Rathke, Andreas, and Dario Izzo. "Keplerian consequences of an impact on an asteroid and their relevance for a deflection demonstration mission." Proceedings of the International Astronomical Union 2, S236 (August 2006): 417–26. http://dx.doi.org/10.1017/s1743921307003511.

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AbstractWe investigate upon the change of an asteroid orbit caused by an impact. We find that, given the assumption of two dimensional motion, the asteroid displacement may be described by an analytic and explicit expression that is the vectorial sum of a radial component and a component along the asteroid velocity. The new formulation bridges the gap between the study of short-term effects, using numerical methods and the analytic study of secular changes of the asteroid orbit. The relation of the method to the established formulations is described and the known results are derived as limiting cases.The application of the new method for the performance evaluation of an asteroid deflection demonstration mission is illustrated. In such a mission the measurement of the change of the asteroid orbit by an impact will be conducted by radio-ranging to a spacecraft orbiting the deflected asteroid. Hence the measurement will primarily be sensitive to the deflection projected onto the Earth-asteroid line of sight. We discuss how the new formulation of the deflection can conveniently be employed for the estimation of the measurement accuracy and the optimal planning of a deflection demonstration mission.

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Zhang, Liufeng, and Yinghua Yang. "Experimental and Numerical Investigation of Short-Term Behavior of Partially Precast and Partially Encased Composite Beams." Slovak Journal of Civil Engineering 28, no. 3 (September 1, 2020): 29–39. http://dx.doi.org/10.2478/sjce-2020-0021.

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AbstractIn this paper, the short-term behavior of a new partially pre-cast and partially encased composite (PPEC) beam is studied. This paper reports the results of a 4-point bending test on a full-scale PPEC beam and sets out the load displacement response, short-term stiffness, peak load capacity and failure mode of the proposed PPEC beam. In addition, a finite element analysis of the PPEC beam is carried out, and the numerical simulation results are compared with the test results. The results show that the finite element model can reflect the bending response of the PPEC beam. In this paper, three different calculation methods are used to compare the deflection of the PPEC beam. The results show that the values calculated by the bending-shear coupling method formula agree relatively well with the test results.

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Zhao, Fei, Chaohe Chen, and Haihao Guo. "Analysis on Flexural Stiffness of GFRP-concrete Hybrid Beams." Open Civil Engineering Journal 11, no. 1 (December 20, 2017): 940–45. http://dx.doi.org/10.2174/1874149501711010940.

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Background: Deferent types of reinforced concrete beams wrapped with GFRP pultruded profiles and a control RC beam are tested under three points loading. Objective: The moment-curvature curves of all tested beams are obtained based on the experimental study. The change characteristics of flexural stiffness for tested beams are analyzed, and the short-term flexural stiffness formula is derived. Results: Finally the computed values of midspan deflection for tested beams are achieved.

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Zeng, Ding, Jun Xie, Xiao-hua Zheng, Hong-wei Ren, and Guo-liang Wang. "Long-Term Deflection Prediction and Correction of Creep and Shrinkage Model of High-Strength Concrete Based on Short-Term Measured Data for Bridge." Journal of Highway and Transportation Research and Development (English Edition) 9, no. 3 (September 2015): 48–54. http://dx.doi.org/10.1061/jhtrcq.0000456.

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Fernandez, Ignasi, Carlos G. Berrocal, and Rasmus Rempling. "Long-Term Performance of Distributed Optical Fiber Sensors Embedded in Reinforced Concrete Beams under Sustained Deflection and Cyclic Loading." Sensors 21, no. 19 (September 22, 2021): 6338. http://dx.doi.org/10.3390/s21196338.

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This paper explores the performance of distributed optical fiber sensors based on Rayleigh backscattering for the monitoring of strains in reinforced concrete elements subjected to different types of long-term external loading. In particular, the reliability and accuracy of robust fiber optic cables with an inner steel tube and an external protective polymeric cladding were investigated through a series of laboratory experiments involving large-scale reinforced concrete beams subjected to either sustained deflection or cyclic loading for 96 days. The unmatched spatial resolution of the strain measurements provided by the sensors allows for a level of detail that leads to new insights in the understanding of the structural behavior of reinforced concrete specimens. Moreover, the accuracy and stability of the sensors enabled the monitoring of subtle strain variations, both in the short-term due to changes of the external load and in the long-term due to time-dependent effects such as creep. Moreover, a comparison with Digital Image Correlation measurements revealed that the strain measurements and the calculation of deflection and crack widths derived thereof remain accurate over time. Therefore, the study concluded that this type of fiber optic has great potential to be used in real long-term monitoring applications in reinforced concrete structures.

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Mirsayapov, Ilshat T., Igor A. Antakov, and Alexey B. Antakov. "To the design of the deflections of flexural concrete members reinforced with fiber-reinforced polymer bars." Vestnik MGSU, no. 4 (April 2021): 413–28. http://dx.doi.org/10.22227/1997-0935.2021.4.413-428.

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Introduction. Fiber-reinforced polymers (FRP) reinforcement has a relatively low modulus of elasticity compared to steel. In this connection, the bent members with such reinforcement have a higher deformability. The stress-strain diagram for FRP under short-term loading is almost straight and does not have a yield line, as in steel reinforcement. At the same time, modern methods of calculating structures with for FRP reinforcement are based on existing approaches for reinforced concrete structures. In this regard, the current direction for study is to assess the reliability and improve the existing methods for calculating members with FRP reinforcement for the serviceability limit states. Materials and methods. Experimental studies were carried with regard for and in compliance with the provisions of National State Standard 8829-94. Tested samples represented concrete beams that were 1,810 mm long and had a cross section of 120 × 220 mm. Their tensile side was reinforced with two bars. Steel, glass fiber-reinforced polymer (GFRP) and basalt fiber-reinforced polymer (BFRP) bars were used to reinforce the beams. The value of the reinforcement ratio varied. Deflections calculation methods, applied according to Construction rules and regulations 295.1325800.2017 (Russia) and ACI 440.1R-06 (USA) were analyzed. Results. The results of the theoretical and experimental studies of the deformability of flexural members having FRP reinforcement are obtained. The inaccurate determination of the cracking moment Mcrc has a negative impact on the results of the deflection calculation. The deviation of the theoretical values of the cracking moment according to the method of Construction rules and regulations 295.1325800.2017 from the experimental ones is 26.2–59.1 %, in the method of ACI 440.1 R-06 — 20.1–57.1 %. For the ACI 440.1 R-06 method, the calculation is more accurate, in which the short-term deflection was multiplied by the factor λ = 0,6ξ = 0,6 · 2 = 1,2, for the Construction rules and regulations 295.1325800.2017 method — when using ψf = 1 – 0,8Mcrc / M. Conclusions. The results obtained showed the need to improve the considered calculation methods. To increase the accuracy of the calculation of deflections according to the method of SP 295.1325800.2017, at the first stage, it is possible to approximate the theoretical values of the cracking moment to the experimental data by introducing correction factor in the equation according to the calculation of Mcrc: for beams with a GFRP high-bond bars — 0.7, for BFRP with a sanded surface — 0.5.

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Feng, Qian, Peng Wei, Xingxi Liu, Guannan Wang, and Rongqiao Xu. "Short-term load–deflection behavior of corroded RC beams with confinement effect based on the partial-interaction segmental approach." Engineering Structures 220 (October 2020): 111014. http://dx.doi.org/10.1016/j.engstruct.2020.111014.

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Han, Xue, Zheng Liu, Xin Xu, and Chao Ge. "Study of Stiffness Calculation Method on Reinforced Concrete Beam Strengthened with CFRP." Advanced Materials Research 744 (August 2013): 455–58. http://dx.doi.org/10.4028/www.scientific.net/amr.744.455.

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The beam member should not only meet the requirement of carrying capacity but also has the ability to resist deformation. The calculation of beam deflection mainly boils down to the stiffness calculation in the existing calculation theory of deformation capacity. The flexural stiffness of concrete beams after strengthened with CFRP has been improved greatly. Direct reinforcement and sustained load reinforcement short-term stiffness calculation methods of CFRP reinforced concrete in normal service stage are derived in this article, which could be used for strengthening design.

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Li, Lei, Yan Xiao, and Rui Zhen Yang. "Experimental Study on Creep and Mechanical Behavior of Modern Bamboo Bridge Structure." Key Engineering Materials 517 (June 2012): 141–49. http://dx.doi.org/10.4028/www.scientific.net/kem.517.141.

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A full-scale testing model of laminated bamboo truck load bridge was made based on the original structure. The mid-span deflection of CFRP-reinforced bamboo girders, temperature and relative air humidity were obtained through over three years creep test under self-weight, and the analysis based on experimental results was finished. The results indicate that the average creep deflection of the girders after three years is approximately 8-mm. In addition, the increase in temperature and humidity may contribute to creep. On the basis of creep test, a short-term loading test was carried out applied with dead load, and the bridge collapsed under the load of 18.5-t. By the analysis of the experimental results, it is realized that long span CFRP-reinforced bamboo girders have sufficient capacity to meet the strength and durability needs of practical use. Although CFRP layers could improve the performance of bamboo girders effectively, there is a decrease in strength and stiffness when considering the long-term performance. All these studies may contribute to improving the design of bamboo bridge structures, and some construction measures are suggested for the bamboo bridge according to the results of the experimental and analysis results.

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Azizi, Aydin, and Ali Ashkzari. "Health Monitoring in Petrochemical Vessels." Advanced Materials Research 1030-1032 (September 2014): 983–86. http://dx.doi.org/10.4028/www.scientific.net/amr.1030-1032.983.

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Industrial structures deteriorate generally in an uncontrollable rate. To assess the short-term impact due to hazards and the long-term deterioration process due to physical aging and routine operation, structural health monitoring (SHM) is proposed. In this paper as a model of vessel a simply supported beam under constant distributed force is investigated. The objective is to estimate the severity of damage in a known location with sensing devices. As no actuation is consider the problem is solved statically. Finite element method by using MATLAB software to calculate the global stiffness matrix of the smart beam has been applied. It is expected the results show that higher severity of damage causes higher deflection and higher sensor of voltage.

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Peshkhoev, I. M. "ASYMPTOTICS OF CRITICAL LOADS OF A COMPRESSED NARROW ELASTIC PLATE WITH INTERNAL STRESSES." Problems of strenght and plasticity 83, no. 2 (2021): 227–34. http://dx.doi.org/10.32326/1814-9146-2021-83-2-227-234.

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The problem of the asymptotic solution of a modified system of nonlinear Karman equilibrium equations for a longitudinally compressed elongated elastic rectangular plate with internal stresses lying on an elastic base is considered. Internal stresses can be caused by continuously distributed edge dislocations and wedge disclinations, or other sources. The compressive pressure is applied parallel to the long sides of the plate to the two short edges. The boundary conditions are considered: the long edges of the plate are free from loads, and the short edges are freely pinched or movably hinged. A small parameter is introduced, equal to the ratio of the short side of the plate to the long side. The solution of the system – the compressive load, the deflection function, and the stress function – is sought in the form of series expansions over a small parameter. The system of Karman equations with dimensionless variables is reduced to an infinite system of boundary value problems for ordinary differential equations with respect to the coefficients of asymptotic expansions for the critical load, deflection, and stress function. In this case, to meet the boundary conditions, the boundary layer functions are additionally introduced, which are concentrated near the fixed edges and disappear when moving away from them. Boundary value problems for determining the functions of the boundary layer are constructed. It is shown that the main terms of the small parameter expansions for the critical load and deflection are determined from the equilibrium equation of a compressed beam on an elastic base with the boundary conditions of free pinching or movable hinge support of the ends. In this case, the main term of the expansion into a series of the stress function has a fourth order of smallness in the parameter of the relative width of the plate.

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Vasyl, Olshanskiy, Burlaka Volodymyr, and Slipchenko Maksym. "PULSE BENDED BEAM WITH BINARY BOUNDARY CONDITIONS." Vibrations in engineering and technology, no. 4(95) (November 20, 2019): 16–23. http://dx.doi.org/10.37128/2306-8744-2019-4-2.

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A theoretical study of the movement of a beam with binary boundary conditions at a short-term pulsed load is carried out in the article. The non-stationary oscillations of the beam, caused by short-term force loading, are evenly distributed along its length. Beam movement is considered in two stages. It is assumed that the conditions for fixing the ends of the beam are associated with the direction (sign) of their rotation when the beam is bending. It is assumed that under the action of the load, the edges of the beam are rigidly clamped, that is, the angles of their rotation are equal to zero, and after unloading and changing the sign of the curvature of the beam they become pivotally supported in cylindrical hinges. According to the second boundary conditions, the free oscillation of the beam passes. Due to the use of the method of compensating loads, the analytical part of the isolation is expressed in rows of sines. Since the system has an asymmetric elastic characteristic with respect to the position of static equilibrium, the method of adding solutions is used to achieve this goal. As a result, the calculation is reduced to the numerical solution of the Volterra type integral equation on a computer. In addition, an approximation is proposed, which gives simpler calculation formulas than a piecewise linear approximation. The proposed approximation allows us to calculate the value of the boundary moments and obtain the formula for the beam deflections. Numerical analysis showed that for certain durations of force loading, the beam deflection amplitude with pinched edges in the direction of the external impulse is less than the deflection amplitude in the opposite direction during the movement of the unloaded beam with hinged edges. This dynamic effect is characteristic of systems with an asymmetric characteristic of elasticity, which occurs when a binary fixing of the edges of the beam or when it is supported by unilateral elastic supports. Formulas are derived by which it is possible to calculate the time when the effect of asymmetry will be most clearly expressed, and also in which case it will be absent. Numerical results confirming the adequacy of the proposed dependencies are presented.

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Rott, Andreas, Bart Doekemeijer, Janna Kristina Seifert, Jan-Willem van Wingerden, and Martin Kühn. "Robust active wake control in consideration of wind direction variability and uncertainty." Wind Energy Science 3, no. 2 (November 12, 2018): 869–82. http://dx.doi.org/10.5194/wes-3-869-2018.

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Abstract. The prospects of active wake deflection control to mitigate wake-induced power losses in wind farms have been demonstrated by large eddy simulations, wind tunnel experiments, and recent field tests. However, it has not yet been fully understood how the yaw control of wind farms should take into account the variability in current environmental conditions in the field and the uncertainty in their measurements. This research investigated the influence of dynamic wind direction changes on active wake deflection by intended yaw misalignment. For this purpose the wake model FLORIS was used together with wind direction measurements recorded at an onshore meteorological mast in flat terrain. The analysis showed that active wake deflection has a high sensitivity towards short-term wind directional changes. This can lead to an increased yaw activity of the turbines. Fluctuations and uncertainties can cause the attempt to increase the power output to fail. Therefore a methodology to optimize the yaw control algorithm for active wake deflection was introduced, which considers dynamic wind direction changes and inaccuracies in the determination of the wind direction. The evaluation based on real wind direction time series confirmed that the robust control algorithm can be tailored to specific meteorological and wind farm conditions and that it can indeed achieve an overall power increase in realistic inflow conditions. Furthermore recommendations for the implementation are given which could combine the robust behaviour with reduced yaw activity.

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Nazri, Mohamed, and Azrulfitri Mohd. "Parametric study on transversal slope and short-term deflection of precast segmental box girder conditions by performing static load test." Journal of Applied Engineering Science 16, no. 2 (2018): 173–84. http://dx.doi.org/10.5937/jaes16-15177.

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Oad, M., B. A. Memon, A. H. Buller, and N. A. Memon. "Flexural Behavior of RC Beams Made with Recycled Aggregates Under 12-Month Long Term Loading." Engineering, Technology & Applied Science Research 9, no. 5 (October 9, 2019): 4631–35. http://dx.doi.org/10.48084/etasr.3013.

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In the present era of infrastructure development, demolishing waste management poses serious problems, particularly in urban centers. Vast development requires huge amounts of conventional concrete aggregates resulting in serious environmental problems. Therefore, efforts are carried out in utilizing demolishing waste, particularly demolishing concrete as coarse aggregates used in new concrete. This article presents laboratory investigations of flexural behavior of reinforced concrete beams made with partial replacement of natural coarse aggregates with coarse aggregates from demolished concrete under 12-month long-term loading. Two batches of beams were cast and cured for 28 days. In the first batch three RC beams with partial replacement of natural coarse aggregates were cast, while in the second batch 6 RC beams with all-natural coarse aggregates were prepared. Out of these six beams three beams were tested under short-term loading to determine maximum load. 50% of this load was used as sustained load on the remaining all beams. The beams were mounted on purpose made frames and deflection, strain, and cracking were recorded on daily basis. After the elapse of the defined time the beams were tested under central point load until failure. Result comparison shows a 4.96% increase in deflection and 2.33% reduction in peak load. Based on the results of this study it is concluded that demolished concrete as coarse aggregates in new concrete shows reasonably good performance under 12-month long-term loading.

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Bonopera, Marco, Kuo-Chun Chang, Chun-Chung Chen, Tzu-Kang Lin, and Nerio Tullini. "Compressive Column Load Identification in Steel Space Frames Using Second-Order Deflection-Based Methods." International Journal of Structural Stability and Dynamics 18, no. 07 (July 2018): 1850092. http://dx.doi.org/10.1142/s021945541850092x.

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This paper presents a comparison of two static nondestructive methods used to assess compressive loads in columns of steel space frames. The first method requires knowledge of the flexural rigidity of the column under investigation, whereas the second method requires knowledge of the column’s buckling load. In each method, short-term displacements are measured at given cross-sections along the member under examination, which is subjected to an additional transverse load. The two methods were verified in this study through experimental and numerical tests on a column of a small-scale space frame prototype with generic connections and end conditions. Estimations of compressive forces were generally reliable when second-order effects were accurately considered. In conclusion, the two methods can be successfully used to test steel space frames in a laboratory or under real conditions.

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Domański, Tomasz, and Kamil Kmiecik. "Probability calibration of deformation factor for timber roofs in the Polish mountain zones." MATEC Web of Conferences 163 (2018): 07003. http://dx.doi.org/10.1051/matecconf/201816307003.

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The resistance parameters of timber material structures decrease with time, depending on the type of load and timber classes. Strength and Modulus of Elasticity reduction effects, referred to as creeprupture effects, due to long term loading at high stress ratio levels are known for many materials. Timber materials are highly affected by this reduction in strength and deflection with duration of load. Characteristic values of load duration and deformation factors are calibrated by means of using probabilistic methods. The reliability is estimated by means of using representative short-and long-term limit states. Time variant reliability aspects are taken into account using a simple representative limit state with time variant strength and simulation of whole life time load processes. The parameters in these models are fitted by the Maximum Likelihood Methods using the data relevant for Polish structural timber . Based on Polish snow data over 45 years from mountain zones in: Zakopane – Tatra, Świeradów – Karkonosze, Lesko – Bieszczady, the snow load process parameters have been estimated. The reliability is evaluated using representative short – and long –term limit states. The deformation factor kdef is obtained using the probabilistic model.

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Akmaluddin, Akmaluddin. "Effect of Tensile Reinforcement Ratio on the Effective Moment of Inertia of Reinforced Lightweight Concrete Beams for Short Term Deflection Calculation." ITB Journal of Engineering Science 43, no. 3 (2011): 209–26. http://dx.doi.org/10.5614/itbj.eng.sci.2011.43.3.4.

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Estévez-Cimadevila, J., D. Otero-Chans, E. Martín-Gutiérrez, and F. Suárez-Riestra. "Testing of different non-adherent tendon solutions to reduce short-term deflection in full-scale timber-concrete-composite T-section beams." Journal of Building Engineering 31 (September 2020): 101437. http://dx.doi.org/10.1016/j.jobe.2020.101437.

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Hjorthaug, Geir A., Endre Søreide, Lars Nordsletten, Jan E. Madsen, Finn P. Reinholt, Sanyalak Niratisairak, and Sigbjørn Dimmen. "Short-term perioperative parecoxib is not detrimental to shaft fracture healing in a rat model." Bone & Joint Research 8, no. 10 (October 2019): 472–80. http://dx.doi.org/10.1302/2046-3758.810.bjr-2018-0341.r1.

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Objectives Experimental studies indicate that non-steroidal anti-inflammatory drugs (NSAIDs) may have negative effects on fracture healing. This study aimed to assess the effect of immediate and delayed short-term administration of clinically relevant parecoxib doses and timing on fracture healing using an established animal fracture model. Methods A standardized closed tibia shaft fracture was induced and stabilized by reamed intramedullary nailing in 66 Wistar rats. A ‘parecoxib immediate’ (Pi) group received parecoxib (3.2 mg/kg bodyweight twice per day) on days 0, 1, and 2. A ‘parecoxib delayed’ (Pd) group received the same dose of parecoxib on days 3, 4, and 5. A control group received saline only. Fracture healing was evaluated by biomechanical tests, histomorphometry, and dual-energy x-ray absorptiometry (DXA) at four weeks. Results For ultimate bending moment, the median ratio between fractured and non-fractured tibia was 0.61 (interquartile range (IQR) 0.45 to 0.82) in the Pi group, 0.44 (IQR 0.42 to 0.52) in the Pd group, and 0.50 (IQR 0.41 to 0.75) in the control group (n = 44; p = 0.068). There were no differences between the groups for stiffness, energy, deflection, callus diameter, DXA measurements (n = 64), histomorphometrically osteoid/bone ratio, or callus area (n = 20). Conclusion This study demonstrates no negative effect of immediate or delayed short-term administration of parecoxib on diaphyseal fracture healing in rats. Cite this article: G. A. Hjorthaug, E. Søreide, L. Nordsletten, J. E. Madsen, F. P. Reinholt, S. Niratisairak, S. Dimmen. Short-term perioperative parecoxib is not detrimental to shaft fracture healing in a rat model. Bone Joint Res 2019;8:472–480. DOI: 10.1302/2046-3758.810.BJR-2018-0341.R1.

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Journal articles on the topic 'Short-term deflection'

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