This study presents rigid-plastic methods of analysis of shear failure in reinforced concrete (R. C.) wall-beam type structures when subjected to in-plane loading. The upper-bound approach is emphasised. Present shear design practice (e.g. BS8110:1985) relies much upon empirical solutions, but it is inadequately Substantiated by theoretical analyses when compared with design against bending moments. Review of previous work on shear failure in R. C. beams demonstrates the need for a rational analysis approach which broadly represents the important physical characteristics and mechanics of shear failure and which can reliably predict the shear capacity. The rigorous theory of plasticity in shear which was introduced by researchers in Denmark in the early 1970's has proved successful for some limited cases. At failure, a simple kinematic rigid-plastic solution was derived for a stringer model with a straight 'yield line'. Recently, evidence has emerged that the best single yield line between two rigid wall portions may well be curved and not straight. There are different stress states in yield lines and consequently three types of yield line are identified in analysis. These findings enable us to apply for the first time combinations of yield lines to analyse shear failure mechanisms of R. C. wall-beam type structures. The principles of rigid-body plane motion are used to describe the deformations of failure mechanisms. The search for the best mechanism at failure is made automatically by computer. The model predicts reasonably well the strength and mechanism for the test results reported in literature. The model is extended to a wall-beam with openings loaded in plane. Tests were made on shallow beams without shear reinforcement and deep beams with and without web openings to study the accuracy of the fundamental calculations made by the model. The most critical mechanism predicted by the model is reasonably representative of the observed failure mechanism. The strength prediction is in substantial agreement with the experimental tests. The conclusions drawn from the study are: (1) If a correct mechanism is predicted then a rigid-plastic solution is close to the true behaviour otherwise it is an upper bound, and (2) The plastic solution of R. C. is only an approximate solution.

Thesis (M.S. in civil engineering)--Washington State University, May 2008. / Includes bibliographical references (p. 53-54).

This research study examined the effect of corrosion of web reinforcement (stirrups) on the shear behaviour of slender reinforced concrete (RC) beams. The experimental program consisted of seventeen slender shear-critical RC beams: five uncorroded and twelve corroded beams. The test variables included: 1) corrosion level (0%, 7.5% and 15%); 2) type of stirrups (smooth and deformed); 3) stirrup diameter (D6, D12 and 10M); 4) stirrups spacing (100mm and 200mm); and 5) the presence of CFRP repair. The corroded beams had their stirrups subjected to corrosion using an accelerated corrosion technique and the mass loss in the stirrups was estimated based on Faraday’s law. All of the beams were monotonically tested to failure in three point bending. The corrosion cracks formed were parallel to the locations of stirrups as evidence of the corrosion damage in the corroded beams. The maximum decrease in the ultimate shear strength ranged from 11% to 14.4% for beams with high corrosion level of 15.6% mass loss. At a low corrosion level (4.39% mass loss), the shear strength of beams with smooth stirrups increased up to 35% due to the enhancement of shear friction at the concrete-corroded stirrups interface. The stiffness of the corroded beams was enhanced in comparison to the control beams. The ultimate deflection of the corroded beams was decreased up to 25% in comparison to the control beams. The CFRP repair increased the shear strength by 36% and improved the overall stiffness by 39% in comparison to the corroded unrepaired beams. All of the unrepaired beams failed in diagonal tension splitting, while the CFRP repaired corroded beams failed in diagonal tension splitting in addition to debonding of the FRP or concrete cover delamination. The actual corrosion mass loss results were in good correlation with Faraday’s law for the D12 and 10M stirrups. Poor correlation between actual and estimated mass loss was obtained for D6 smooth stirrups, possibly due to errors in the impressed corrosion. iv The analytical model used the modified compression field theory (MCFT) to predict the shear strength of uncorroded and corroded slender RC beams. In the corroded beams, two reduction factors were added to the MCFT model including the mass loss factor and the effective web width. Predictions based on the model revealed that the control beams gave a very good correlation with the ratio of experimental to predicted values that ranged from 0.94 to 1.02. On other hand, the ratio of experimental to predicted strength in the corroded beams ranged between1.06 to 1.4. The poor correlations were obtained for the beams with the D6 smooth stirrups. This study demonstrates that corrosion of web reinforcement can have a detrimental effect on the shear strength and ductility of slender shear-critical RC beams. The experimental results and analytical approach will be very useful for practicing engineers and researchers dealing with corrosion damage in slender RC members.

This research study examined the effect of corrosion of web reinforcement (stirrups) on the shear behaviour of slender reinforced concrete (RC) beams. The experimental program consisted of seventeen slender shear-critical RC beams: five uncorroded and twelve corroded beams. The test variables included: 1) corrosion level (0%, 7.5% and 15%); 2) type of stirrups (smooth and deformed); 3) stirrup diameter (D6, D12 and 10M); 4) stirrups spacing (100mm and 200mm); and 5) the presence of CFRP repair. The corroded beams had their stirrups subjected to corrosion using an accelerated corrosion technique and the mass loss in the stirrups was estimated based on Faraday’s law. All of the beams were monotonically tested to failure in three point bending. The corrosion cracks formed were parallel to the locations of stirrups as evidence of the corrosion damage in the corroded beams. The maximum decrease in the ultimate shear strength ranged from 11% to 14.4% for beams with high corrosion level of 15.6% mass loss. At a low corrosion level (4.39% mass loss), the shear strength of beams with smooth stirrups increased up to 35% due to the enhancement of shear friction at the concrete-corroded stirrups interface. The stiffness of the corroded beams was enhanced in comparison to the control beams. The ultimate deflection of the corroded beams was decreased up to 25% in comparison to the control beams. The CFRP repair increased the shear strength by 36% and improved the overall stiffness by 39% in comparison to the corroded unrepaired beams. All of the unrepaired beams failed in diagonal tension splitting, while the CFRP repaired corroded beams failed in diagonal tension splitting in addition to debonding of the FRP or concrete cover delamination. The actual corrosion mass loss results were in good correlation with Faraday’s law for the D12 and 10M stirrups. Poor correlation between actual and estimated mass loss was obtained for D6 smooth stirrups, possibly due to errors in the impressed corrosion. iv The analytical model used the modified compression field theory (MCFT) to predict the shear strength of uncorroded and corroded slender RC beams. In the corroded beams, two reduction factors were added to the MCFT model including the mass loss factor and the effective web width. Predictions based on the model revealed that the control beams gave a very good correlation with the ratio of experimental to predicted values that ranged from 0.94 to 1.02. On other hand, the ratio of experimental to predicted strength in the corroded beams ranged between1.06 to 1.4. The poor correlations were obtained for the beams with the D6 smooth stirrups. This study demonstrates that corrosion of web reinforcement can have a detrimental effect on the shear strength and ductility of slender shear-critical RC beams. The experimental results and analytical approach will be very useful for practicing engineers and researchers dealing with corrosion damage in slender RC members.

Non-ductile reinforced concrete frame buildings constitute an important part of the vulnerable buildings in seismic regions of the world. Collapse of non-ductile multi story concrete buildings during strong earthquakes in the past resulted in severe casualties and economic losses. Their rehabilitation through retrofitting is a critical issue in reducing seismic risks worldwide. A displacement-based retrofitting approach is presented in this study for seismic retrofitting of medium height non-ductile concrete frames. A minimum amount of shear walls are added for maintaining the deformation levels below the critical level dictated by the existing columns in the critical story, which is usually at the ground story. Detailing of shear walls are based on conforming to the reduced deformation demands of the retrofitted frame/wall system. Member-end rotations are employed as the response parameters for performance evaluation. Initial results obtained from the proposed displacement based approach have revealed that jacketing of columns and confining the end regions of added shear walls are usually unnecessary compared to the conventional force-based approach, where excessive force and deformation capacities are provided regardless of the actual deformation demands.

Over 90% of the land area of Turkey lies over one of the most active seismic zones in the world. Hazardous earthquakes frequently occur and cause heavy damage to the economy of the country as well as human lives. Unfortunately, the majority of buildings in Turkey do not have enough seismic resistance capacity. The most commonly observed problems are faulty system configuration, insufficient lateral stiffness, improper detailing, poor material quality and mistakes during construction. Strengthening of R/C framed structures by using cast-in-place R/C infills leads to a huge construction work and is time consuming. On the other hand, using prefabricated panel infills can be preferred as a more feasible, rapid and easy technique during which the structure can remain operational. The aim of this experimental study is to observe the seismic behavior of R/C frames strengthened by precast concrete panel infills by testing different types of panel and connection designs in eight single-story single-bay reinforced concrete frame specimens.

This diploma thesis deals with the analysis of reinforced concrete structure with masonry walls. Scia Engineer was used for finite element analysis. The spatial models include nonlinear behavior of masonry. Furthermore, the ceiling slab above the 1st floor, beams and columns were designed.

The subject of the diploma thesis is a project documentation of a multifunctional building within the scope of the implementing documentation. The main goal of the thesis is the design of the layout, construction and material solution, completed by design of the fire safety solutions and assessment in terms of building physics. The multifunctional building has one underground floor and nine above-ground floors. In the basement there are technical facilities of the building and a parking area, in the 1st floor there are business premises, in one part of the 2nd floor there is a gym and the remaining areas are used for administrative purposes as well as the entire 3rd to 9th floor. The construction system is designed as a reinforced concrete monolithic skeleton, completed by a reinforced concrete core. Ceiling structures are monolithic reinforced concrete locally supported slabs. The building is founded on the concrete slab placed on drilled shafts. The main element of the outer wall is curtain walling, which is made from a mullion-transom system.