Yes / Nine continuous concrete deep beams reinforced with glass fibre reinforced polymer (GFRP) bars were experimentally tested to failure. Three main parameters were investigated, namely, shear span-to-overall depth ratio, web reinforcement and size effect. The experimental results confirmed the impacts of web reinforcement and size effect that were not considered by the strut-and-tie method (STM) of the only code provision, the Canadian S806-12, that addressed such elements. The experimental results were employed to evaluate the applicability of the methods suggested by the American, European and Canadian codes as well as the previous studies to predict the load capacities of continuous deep beams reinforced with GFRP bars. It was found that these methods were unable to reflect the influences of size effect and/or web reinforcement, the impact of which has been confirmed by the current experimental investigation. Therefore, a new effectiveness factor was recommended to be used with the STM. Additionally, an upper-bound analysis was developed to predict the load capacity of the tested specimens considering a reduced bond strength of GFRP bars. A good agreement between the predicted results and the experimental ones was obtained with the mean and coefficient of variation values of 1.02 and 5.9%, respectively, for the STM and 1.03 and 8.6%, respectively, for the upper-bound analysis. / Higher Committee of Education Development in Iraq (HCED)

yes / There are very few, if any, available experimental investigations on aggregate interlock capacity along diagonal cracks in lightweight concrete deep beams. As a result, the shear design provisions including the modification factor of ACI 318-08 and EC 2 for lightweight concrete continuous deep beams are generally developed and validated using normal weight simple deep beam specimens. This paper presents the testing of 12 continuous beams made of all-lightweight, sand-lightweight and normal weight concrete having maximum aggregate sizes of 4, 8, 13 and 19 mm. The load capacities of beams tested are compared with the predictions of strut-and-tie models recommended in ACI 318-08 and EC 2 provisions including the modification factor for lightweight concrete. The beam load capacity increased with the increase of maximum aggregate size, though the aggregate interlock contribution to the load capacity of lightweight concrete deep beams was less than that of normal weight concrete deep beams. It was also shown that the lightweight concrete modification factor in EC 2 is generally unconservative, while that in ACI 318-08 is conservative for all-lightweight concrete but turns to be unconservative for sand-lightweight concrete with a maximum aggregate size above 13 mm. The conservatism of the strut-and-tie models specified in ACI 318-08 and EC 2 decreased with the decrease of maximum aggregate size, and was less in lightweight concrete deep beams than in normal weight concrete deep beams.

Several reinforced concrete bent caps (deep beams) in Texas have developed significant diagonal cracks in service. The cracking in two bent caps was so extensive that costly retrofits were implemented to strengthen the structures. Strut-and-tie modeling is currently recommended in most U.S. design specifications for the design of reinforced concrete bent caps and deep beams. Designers have expressed concerns with the lack of clarity and serviceability-related considerations in strut-and-tie model design provisions. Due to concerns with strut-and-tie modeling design provisions and field problems of in-service bent caps, TxDOT Project 5253 was funded. Several tasks conducted within Project 5253 are addressed in this dissertation. The effects of minimum web reinforcement and member depth on the strength and serviceability behavior of deep beams are presented. The transition between deep beam shear capacity and sectional shear capacity near a shear-span-to-depth (a/d) ratio of 2 is addressed. A service-load shear check to limit diagonal cracking in service is outlined. Lastly, a simple chart that correlates the maximum width of diagonal cracks in a deep beam to its residual capacity is developed. To accomplish the objectives of Project 5253, thirty-seven tests were conducted on reinforced concrete beams with the following cross-sectional dimensions: 21”x23”, 21”x42”, 21”x44”, 21”x75”, and 36”x48.” The specimens were loaded with a/d ratios of 1.2, 1.85, and 2.5. The test specimens are among the largest reinforced concrete deep beams in the literature. To supplement the findings of the experimental program, a database of deep beam test results was compiled. Entries in the database that lacked sufficient information and that did not meet established cross-sectional size or web reinforcement criteria were filtered from the database. The use of the database in conjunction with the experimental program enabled each objective to be addressed from both broad and specific viewpoints. Several recommendations for improving the strength and serviceability design of deep beams are presented including a minimum web reinforcement requirement, provisions to ease the transition between calculated deep beam and sectional shear capacity, and a design check to limit diagonal cracking in service. / text

The present research is conducted to investigate the structural behaviour of continuously supported deep beams made with SCC. A series of tests on eight reinforced two-span continuous deep beams made with SCC was performed. The main parameters investigated were the shear span-to-depth ratio, the amount and configuration of web reinforcement and the main longitudinal reinforcement ratio. All beams failed due to a major diagonal crack formed between the applied mid-span load and the intermediate support separating the beam into two blocks: the first one rotated around the end support leaving the rest of the beam fixed on the other two supports. The amount and configuration of web reinforcement had a major effect in controlling the shear capacity of SCC continuous deep beams. The shear provisions of the ACI 318M-11 reasonably predicted the load capacity of SCC continuous deep beams. The strut-and-tie model recommended by different design codes showed conservative results for all SCC continuous deep beams. The ACI Building Code (ACI 318M-11) predictions were more accurate than those of the EC2 and Canadian Code (CSA23.3-04). The proposed effectiveness factor equations for the strut-and-tie model showed accurate predictions compared to the experimental results. The different equations of the effectiveness factor used in upper-bound analysis can reasonably be applied to the prediction of the load capacity of continuously supported SCC deep beams although they were proposed for normal concrete (NC). The proposed three dimensional FE model accurately predicted the failure modes, the load capacity and the load-deflection response of the beams tested.

Submitted by Cláudia Bueno (claudiamoura18@gmail.com) on 2016-01-29T14:45:57Z No. of bitstreams: 2 Dissertação - Flávio Augusto Xavier Carneiro Pinho - 2015.pdf: 5478560 bytes, checksum: 3507be4593cbd586348d2f5a2bfe2f9f (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2016-02-01T11:53:05Z (GMT) No. of bitstreams: 2 Dissertação - Flávio Augusto Xavier Carneiro Pinho - 2015.pdf: 5478560 bytes, checksum: 3507be4593cbd586348d2f5a2bfe2f9f (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Made available in DSpace on 2016-02-01T11:53:05Z (GMT). No. of bitstreams: 2 Dissertação - Flávio Augusto Xavier Carneiro Pinho - 2015.pdf: 5478560 bytes, checksum: 3507be4593cbd586348d2f5a2bfe2f9f (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Previous issue date: 2015-04-10 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Optimization techniques have been widely used in different engineering applications. In the case of structural conception, these techniques can be applied from the architectural concept, determining, for example, bracing structures to setting the best topology for concrete structures, as those compared to strut and tie models. In this context, this thesis presents techniques applied to topology optimization in subsystems of buildings. It is also presented a new software tool, modelled in object-oriented programming, seeking the solution for topology optimization problems assembling various technical problems unified in a single approach. The software tool was used to determine the best shape to bracing frames on a building submited to different loading combinations as well to compare the strut and tie models to foundation blocks. Results were compared to literature review, validating the unified computational procedure. Strut and tie models found in literature were compared to piled foundation blocks varying the number of piles, and whose geometry for larger number of piles are still not clearly defined. / Técnicas de otimização têm sido especialmente utilizadas em diversos problemas de engenharia. No caso da concepção estrutural de grandes edifícios, essas técnicas podem ser utilizadas desde o partido arquitetônico. Neste caso, podem ser determinadas, por exemplo, estruturas de contraventamento. Outro exemplo é a aplicação da otimização de topologia para determinação do modelo de bielas e tirantes de estruturas de concreto armado. Neste trabalho, são utilizadas técnicas de otimização de topologia aplicadas em subsistemas de edifícios. Apresenta-se um software em linguagem de programação orientada a objeto para a solução de problemas de otimização de topologia em que são reunidas diferentes técnicas características do problema as quais são unificadas em uma única abordagem. Esse software é aplicado para determinar a melhor forma da estrutura de contraventamento de edifícios altos submetidos a diversas combinações de carregamentos e para determinação do modelo de bielas e tirantes de blocos de fundações. Os resultados encontrados validam a utilização da uma abordagem unificada já que são condizentes com a literatura. Os modelos de bielas e tirantes encontrados para os blocos de fundações são iguais aos modelos clássicos encontrados na literatura. Também foram estudados blocos de fundações com uma maior quantidade de estacas cujos modelos ainda não possuem geometria bem definida na literatura.

This work deals with the structural solution of selected parts of load bearing structure of apartment house - floor slabs of 1.PP and 2.NP, deep beam and its supporting column. The analysis is made by Finite Element Method, deep beam is solved by Strut-and-Tie model. The elements are designed and assessed according to valid standards.

This work deals with the structural solution of reinforced concrete floor slab, deep beam and its support of multipurpose building. The structure is designed and assessed in according to valid standards. The continuous one-way slab is analyzed by Finite Element Method, deep beam is solved by Strut-and-Tie model.

The present research is conducted to investigate the structural behaviour of continuously supported deep beams made with SCC. A series of tests on eight reinforced two-span continuous deep beams made with SCC was performed. The main parameters investigated were the shear span-to-depth ratio, the amount and configuration of web reinforcement and the main longitudinal reinforcement ratio. All beams failed due to a major diagonal crack formed between the applied mid-span load and the intermediate support separating the beam into two blocks: the first one rotated around the end support leaving the rest of the beam fixed on the other two supports. The amount and configuration of web reinforcement had a major effect in controlling the shear capacity of SCC continuous deep beams. The shear provisions of the ACI 318M-11 reasonably predicted the load capacity of SCC continuous deep beams. The strut-and-tie model recommended by different design codes showed conservative results for all SCC continuous deep beams. The ACI Building Code (ACI 318M-11) predictions were more accurate than those of the EC2 and Canadian Code (CSA23.3-04). The proposed effectiveness factor equations for the strut-and-tie model showed accurate predictions compared to the experimental results. The different equations of the effectiveness factor used in upper-bound analysis can reasonably be applied to the prediction of the load capacity of continuously supported SCC deep beams although they were proposed for normal concrete (NC). The proposed three dimensional FE model accurately predicted the failure modes, the load capacity and the load-deflection response of the beams tested. / Higher Education Institute in the Libyan Government

Esta pesquisa estuda o comportamento de blocos de concreto armado sobre duas estacas com cálice totalmente embutido, utilizado na ligação pilar-fundação de estruturas de concreto pré-moldado. Particularmente, foi avaliado o efeito que a viga de travamento provoca no bloco quando apoiada nas paredes laterais do cálice. Foi desenvolvida análise numérica tridimensional utilizando programa baseado no método dos elementos finitos (MEF), na qual foi considerada a não-linearidade física dos materiais. Para avaliação do programa adotado, realizou-se análise comparativa de resultados experimentais e numéricos obtidos por meio de outro programa. Nos blocos estudados variou-se a espessura e o tipo de conformação das paredes do cálice, o ângulo de inclinação da biela e a intensidade das ações na viga de travamento. Os resultados indicam que a presença da viga de travamento não altera de modo significativo o comportamento do bloco, e que a parede do cálice é capaz de transferir a força proveniente da viga em direção às estacas de modo eficaz. Por meio das tensões nas barras da armadura principal, foi possível obter a força no tirante e o ângulo de inclinação da biela antes da ruína dos modelos. Constatou-se que os ângulos apresentaram maior inclinação do que as utilizadas no dimensionamento, que por sua vez foi feito baseado nos modelos de bielas e tirantes. / The present research studies the behavior of two pile caps reinforced concrete with embedded socked used in connections of pre-cast concrete structures. It was particularly evaluated the effect provoked by the locking beam on the pile-caps when supported by the socket lateral walls. Three-dimensional numerical analyses using software based on finite element method (FEM) were developed considering the nonlinear physical behavior of the material. To evaluate the adopted software, a comparative analysis was made using numerical and experimental results obtained from other software. In the pile caps studied, it was noticed a variation in the wall thickness, socket interface, strut angle inclination and action on beam. The results show that the presence of beam does not change significantly the pile caps behavior and that the socket wall is able to transfer effectively the force from the beam to the pile caps. By the tensions on the bars of longitudinal reinforcement, it was possible to obtain the force on the tie and the strut angle inclination before the collapse of models. It was found that the angles present more inclinations than those used in the design, which was made based on strut and tie model.

A racionalização e a industrialização da construção civil têm promovido o sistema construtivo baseado em elementos de concretos pré-moldados. O comportamento das ligações entre os elementos pré-moldados constitui uma das principais preocupações dos projetistas, sendo as ligações entre a superestrutura e as fundações determinantes na estabilidade e na distribuição de esforços solicitantes da estrutura. O comportamento de blocos sobre estacas com ligações para pilares pré-moldados possui particularidades em razão do diferente mecanismo de transferência de forças do pilar para o bloco mediante a ligação. Neste trabalho é estudado o comportamento de blocos de fundação apoiados sobre quatro estacas com cálice totalmente embutido para ligação com pilar pré-moldado. O estudo baseou-se em análise numérica não-linear de modelos tridimensionais considerando a fissuração do concreto, a presença de armadura e a interface de ligação. O comportamento de blocos com pilares submetidos à força vertical centrada e excêntrica foi descrito em termos de força última, panorama de fissuração, fluxo de tensões principais e tensões nas armaduras do bloco. Os resultados indicam a ocorrência de transferência de esforços do pilar para a fundação a partir das paredes do cálice de interface lisa, entretanto com intensidade insuficiente para a formação de bielas de compressão, e o risco da ocorrência de punção em blocos onde os pilares são ligados por cálices de paredes lisas. / The rationalization and the industrialization of the civil constructions have stimulated the construction process based on precast elements. One of the main designer\'s worries is about the behavior of the joints between precast elements, and the joints between superstructure and the foundations which are determinant in the construction stability and behavior of elements. In reason of the mechanism of transference of the forces from column to pile-cap by socket connections, the behavior of pile-caps with joints for precast columns has some specificity. The behavior of four-pile caps with embedded socket for precast columns joints is studied in this research. The study is based in nonlinear numerical analysis of three dimensional models considering the cracking in concrete, the reinforcement and the joint interface. The behavior of pile caps under centered and eccentric vertical force is described by ultimate force, cracking patterns, principal stresses flow and reinforcements strains. The results suggests that occurs the transfer of forces from column to the pile cap in the socket walls with smooth interface, however the intensity is not enough to form the struts, and the risk of development of punching shear in pile caps which columns are connected by smooth interface socket walls.