Seismic Evaluation and Retrofit of Existing Buildings

Abstract

When evaluating and improving seismic capacity of existing buildings 'seismic safety evaluation' and 'retrofitting' are very important tasks. Engineers evaluate structures with different methods. The presented method combines experimental data and engineering knowledge in order to evaluate seismic safety factors and expected structural performance under strong events. Distinction between the structures with and those without problems are made. This is also a quick way to check the response of structures to expected seismic activities. The method could also be used for choosing the optimal strengthening method and to verify the quality of performed strengthening works. Proposed methodology is explained on the example of two buildings with the explanation of performed strengthening methods. The construction price of retrofitted buildings is compared to the price of demolishing the existing and building a new building.

Strength and stiffness estimation of damaged reinforced concrete shear walls using crack patterns

“…Seismic analysis and post-earthquake evaluation of structures have received much attention in recent years. 17,45,46 Evaluation of the damage severity of existing buildings after an earthquake is of great importance to assure residents of the buildings that the damaged building is safe or unsafe. On the other hand, performance level of new or existing buildings is usually assessed by analyzing the drift ratio that the structure has experienced during the earthquake.…”

“…For these purposes, several parameters are introduced as an indicator of the damage level of a building. Crack width, 46 story drift ratio, 45 and stiffness degradation 15,47 are representatives of the damage condition in concrete buildings. These parameters are essentially alternatives to the residual strength of buildings after an earthquake, which is not simple to be obtained.…”

“…The acceptable total drift of RCSWs governed by shear failure mode shall be specified in Table 9 by ASCE41-17. 45 The performance level depends on the axial load ratio of the shear wall. Figure 8 shows the relation between STD and SFD with the experienced drift ratios of the walls and also the performance levels, that is, immediate occupancy, life safety, and collapse prevention.…”

A study on the accuracy of force analogy method in nonlinear static analysis

“…The values of a, b, and c were calculated based on Table 9.7.1 of ASCE41-17. [21] For the fiber-based distributed plasticity methods, the number of fibers in the sections and number of integration points along the members are shown in Figure 10. The material used for fiber sections is the OpenSees Steel01 material with the post-yield tangent equal to 10% of its initial elastic tangent.…”

Fuzzy AHP Method for Selection of a Suitable Seismic Retrofitting Alternative in Low-Rise Buildings

“…According to codes such as FEMA 356 [1], ASCE /SEI 41-17 [2], NZSEE [3], BS EN 1998-3 [4] and IRI 360 [5], all the old buildings which do not meet the criteria of the codes, should be evaluated with regard to their resistances against earthquake. They probably need to be retrofitted due to some deficiencies related to their gravitational and lateral resistances, material and construction weaknesses.…”