A database comprised of 59 reinforced concrete columns subjected to strong ground shaking using earthquake simulators (or shaking tables) is compiled. This paper will focus on insights provided by the database related to the concrete column provisions in ASCE/SEI 41. In particular, the Shaking Table Test Column Database is used to evaluate the accuracy of column effective stiffness models, column classification criteria, and the level of conservatism provided by the plastic rotation capacities specified in ASCE/SEI 41. It is found that the Standard generally overestimates the column effective stiffness, while providing a mean value estimate of the column shear strength regardless of tie spacing. The modeling parameters specified in the standard provide conservative estimate of the column drift capacities and are consistent with the targeted probability of failure. Refinements of the shear strength model and the criteria for column classifications are suggested. This study also compares the measured response of columns subjected to quasi-static cyclic loads and shaking table tests.

The results of laboratory testing and earthquake reconnaissance studies of reinforced concrete frames indicate that beam‐column joint deformation can determine total frame deformation and that for older buildings joint failure can result in frames losing lateral and gravity load carrying capacity. Given the impact of joints on frame response, numerical models used to evaluate the earthquake performance of reinforced concrete frames must include nonlinear joint models. This paper reviews previously proposed models for simulating joint response with the objective of identifying models that provide i) accurate simulation of response to earthquake loading, ii) simple implementation in nonlinear analysis software, iii) numerical robustness, iv) computational efficiency, and v) objective calibration procedures. Ultimately, no set of models was identified that met all of these requirements for the range of geometric and design parameters found in reinforced concrete buildings in the United States. With the objective of extending current modeling capabilities for interior joints, an experimental data set was assembled. The data set was used to evaluate existing envelope response models and used to calibrate cyclic response parameters for use with the preferred existing model. A new response model for interior beam‐column joints is presented that meets the above requirements for the range of geometric and design parameters found in reinforced concrete buildings in the United States.

Case studies on seismic assessment and rehabilitation of reinforced concrete buildings are discussed based on the projects in which Degenkolb Engineers has been involved in the past 5 years. Design, analysis and challenges are discussed to present applications of ASCE 31-03, Seismic Evaluation of Existing Buildings and ASCE 41-06, Seismic Rehabilitation of Existing Buildings.

The assessment of the seismic vulnerability and collapse potential of masonry‐infilled RC frame buildings presents a significant challenge because of the complicated failure mechanisms they could exhibit and the number of factors that could affect their behavior. In general, there are two types of analysis methods that can be used to simulate the inelastic behavior of infilled frames. One is to use simplified frame models in which infill walls are represented by equivalent diagonal struts, and the other is to use refined finite element models that can capture the failure behavior of RC frames and infill walls in a detailed manner. However, both types of models have limitations in simulating structural response through collapse. While refined finite element models are not computationally efficient, simplified models are less accurate because of their inability to represent some failure mechanisms that could occur in an infilled frame. In this paper, possible failure mechanisms and causes of collapse of masonry‐infilled RC structures are discussed, and both simplified and refined finite element analysis methods that can be used to simulate the inelastic response of these structures and assess their vulnerability to collapse are presented with numerical examples. Additional research and development work needed to improve collapse simulations is discussed.

A new law known as the "Urban Renewal Law" for risk mitigation was passed in May 2012 with the objective of reducing seismic risk associated with the existing building stock in Turkey. As stated in the law, new provisions are set forth to assess and to identify seismically vulnerable residential buildings as quickly as possible. The buildings that are classified as high risk are either demolished or strengthened. New buildings are constructed through the financing options provided by the government. In this study, first, the technical provisions of seismic risk assessment, based on linear elastic analysis, are briefly described with special emphasis on the deformation limits. Because of the inability of the linear elastic analysis to allow for redistribution, some flexibility is provided on how many vertical load bearing elements are allowed to exceed their performance limits. Afterwards, three case study buildings are analyzed by using the new provisions and ASCE/SEI 41-06 linear elastic procedure. Level and sources of conservatism in the two approaches are critically evaluated.