A Displacement-Based Approach for the Seismic Retrofitting of Medium Rise Non-Ductile RC Frames with Added Shear Walls

2011 ◽  
Vol 15 (6) ◽  
pp. 959-969 ◽  
Author(s):  
H. Sucuoğlu ◽  
C. Karageyik
Keyword(s):  
Shear Walls ◽  
Seismic Retrofitting ◽  
Rc Frames ◽  
Displacement Based

scholarly journals The High-Performance Dissipating Frame (HPDF) System for the Seismic Strengthening of RC Existing Buildings

2021 ◽  
Vol 13 (4) ◽  
pp. 1864
Author(s):  
Vincenzo Manfredi ◽  
Giuseppe Santarsiero ◽  
Angelo Masi ◽  
Giuseppe Ventura
Keyword(s):  
High Performance ◽  
Design Procedure ◽  
Seismic Retrofitting ◽  
Existing Buildings ◽  
Sustainable Solutions ◽  
Seismic Rehabilitation ◽  
Existing Structures ◽  
Rc Frames ◽  
Frame System ◽  
Displacement Based

In Italy as well as in other earthquake-prone countries, the large number of existing buildings requiring seismic retrofitting calls for sustainable solutions able to reduce both costs and downtime. To this purpose, in this paper, the High-Performance Dissipating Frame system (HPDF), a new strengthening solution for the seismic rehabilitation of existing buildings, is presented. HPDF is based on external precast reinforced concrete (RC) frames rigidly connected to the existing structures and equipped with shear damper devices in order to provide high dissipation capacity. The proposed solution permits: (i) to increase sustainability through works made up from the outside without removing/demolishing infills/other non-structural components, (ii) rapid execution by adopting precast resisting members mutually restrained with steel connections, and (iii) effectiveness due to shear damper devices able to dissipate a large amount of shaking energy. In the paper, a displacement-based design procedure is proposed and applied to a numerical example.

A Displacement-Based Optimal Design Method of RC Frames Subjected to Minor Earthquakes

2012 ◽  
Vol 594-597 ◽  
pp. 795-799
Author(s):  
Gui Tao Chen ◽  
De Min Wei
Keyword(s):  
Optimal Design ◽  
Optimization Design ◽  
Virtual Work ◽  
Design Method ◽  
Horizontal Displacement ◽  
Target Displacement ◽  
Programming Technique ◽  
Direct Displacement Based Design ◽  
Rc Frames ◽  
Displacement Based

A displacement-based optimization design method of RC structure was proposed by combining direct displacement-based design method with nonlinear programming technique. To avert the influence of target displacement, the stationary constraint displacement was presented, and the target displacement can be updated during the optimal design process. Principle of virtual work and Gaussian integral method was employed to simplify the explicit relationship between horizontal displacement and the section dimension. Comparison analysis of the local optimal results corresponding to different displacement shapes was conducted to achieve global optimal design. The numerical tests presented demonstrate the computational advantages of the discussed methods and suggesting that the proposed method is a reliably and efficiently tool for displacement-based optimal design.

Displacement-based seismic design for buildings installed hysteretic dampers with hardening post-yielding stiffness

2019 ◽  
Vol 22 (16) ◽  
pp. 3420-3434 ◽  
Author(s):  
Gang Li ◽  
Li-Hua Zhu ◽  
Hong-Nan Li
Keyword(s):  
Energy Dissipation ◽  
Yield Strength ◽  
Seismic Design ◽  
Structural Control ◽  
Seismic Retrofitting ◽  
Maximum Displacement ◽  
Hardening Behavior ◽  
Displacement Based ◽  
Hysteretic Dampers ◽  
Displacement Based Seismic Design

Passive energy dissipation devices have been proved to be effective and low-cost means of structural control, and a variety of dampers have been developed over the past decades. Hysteretic dampers with hardening post-yielding stiffness have multiphased energy dissipation characteristics because of their hardening behavior, which can compensate for stiffness loss and postpone the collapse of damaged structures. In this article, a hysteretic model is proposed for hysteretic dampers with hardening post-yielding stiffnesses, and a formula is derived for equivalent yield strength expressed by the additional damping of the structure. A procedure is developed for displacement-based seismic design that transforms the relatively complex damping into an acceptable yield strength. A numerical example is only presented for demonstrating the design process and simply validating the proposed method. The results show that the proposed procedure is easy to implement and could produce adequate hysteretic dampers with hardening post-yielding stiffness hardening behavior. The maximum displacement responses of the existing structure retrofitted using the proposed procedure satisfy the expected performance objective well. Thus, this procedure could be an alternative to seismic retrofitting for structures with energy dissipation systems.

Retrofitting Non-Ductile RC Frames for Seismic Resistance Using Post-Installed Shear Walls

2019 ◽  
Author(s):  
Chien-Kuo Chiu ◽  
Fu-Pei Hsiao ◽  
Wen-I Liao ◽  
Samuel Jonathan Quacoo ◽  
Chin-En Ho ◽  
...  
Keyword(s):  
Brittle Failure ◽  
Load Transfer ◽  
Shear Walls ◽  
Frame Structures ◽  
Seismic Capacity ◽  
Rc Structures ◽  
Structural Health ◽  
Rc Frames ◽  
Lateral Strength ◽  
Rc Frame Structures

Abstract Reinforced Concrete (RC) frame structures that were designed and built according to older standards can be damaged during destructive earthquakes as a result of insufficient lateral strength and/or deformation capacity. Such structures must be retrofitted to satisfy the current requirements and to survive future earthquakes. Owing to its high lateral strength and stiffness capacity of an RC wall, the post-installation of an RC wall in a non-ductile frame for retrofit is a widely used retrofitting technique. However, for frame structures with low-strength concrete, the typically used connected construction method on the interface between existing and new concrete may be not able to provide effective force transfer, and may cause unexpected brittle failure in the retrofitted structure. Such unexpected brittle failure may reduce the seismic capacity of the structure and threaten its safety. Therefore, in this experimental investigation, two retrofitting methods that use a post-installed RC wall are proposed to improve the load transfer mechanism on the interface. The first involves a wall with diagonal rebar and boundary spirals, and the second involves a wall with an additional inner frame. A typical traditional retrofitting specimen was constructed and tested for comparison. Reversed cyclic loading is used to test the seismic capacity of the specimens. Finally, post-embedded piezoceramic-based sensors were used to monitor the structural health and detect damage in one of specimens during the test. The experimental results demonstrate the effectiveness of the piezoceramic-based approach to structural health monitoring and the ability of the method to detect damage in shear governed RC structures under seismic loading.

scholarly journals Simplified Data-Driven Model for the Moment Curvature of T-Shaped RC Shear Walls

2019 ◽  
Vol 2019 ◽  
pp. 1-16 ◽  
Author(s):  
Bin Wang ◽  
Wenzhe Cai ◽  
Qingxuan Shi
Keyword(s):  
Cross Sections ◽  
Limit State ◽  
Shear Walls ◽  
Load Ratio ◽  
Ultimate Limit State ◽  
Limit States ◽  
Displacement Ductility ◽  
And Performance ◽  
Displacement Based ◽  
Ductility Capacity

Sectional deformation quantities, such as curvature and ductility, are of prime significance in the displacement-based seismic design and performance evaluation of structural members. However, few studies on the estimates of curvatures at different limit states have been performed on asymmetric flanged walls. In this paper, a parametric study was performed for a series of T-shaped wall cross-sections based on moment-curvature analyses. By investigating the effects of the axial load ratio, reinforcement content, material properties, and geometric parameters on curvatures at the yield and ultimate limit state, we interpret the variation in curvature with different influencing factors in detail according to the changes of the neutral axis depth. Based on the regression analyses of the numerical results of 4941 T-shaped cross-sections, simple expressions to estimate the yield curvature and ultimate curvature for asymmetric flanged walls are developed, and simplified estimates of the ductility capacity including curvature ductility and displacement ductility are further deduced. By comparing with the experimental results, we verify the accuracy of the proposed formulas. Such simple expressions will be valuable for the determination of the displacement response of asymmetric flanged reinforced concrete walls.

Displacement-Based Seismic Design of Steel Frames Strengthened by Buckling-Restrained Braces

2012 ◽  
Vol 217-219 ◽  
pp. 1114-1118 ◽  
Author(s):  
Marco Valente
Keyword(s):  
Steel Frames ◽  
Design Procedure ◽  
Steel Frame ◽  
Seismic Retrofitting ◽  
Target Displacement ◽  
Earthquake Excitation ◽  
Capacity Spectrum ◽  
Buckling Restrained Braces ◽  
Displacement Based ◽  
Nonlinear Dynamic Analyses

This study presents a displacement-based design procedure for seismic retrofitting of steel frames using buckling-restrained braces (BRB) to meet a given target displacement in the framework of the capacity spectrum method. The seismic performance of a six-storey steel frame equipped with BRB is investigated. Different storey-wise BRB distribution methods are proposed and the influence on the results of the design procedure is analyzed. Nonlinear dynamic analyses demonstrate the efficacy of the design procedure showing the improvements achieved by the retrofitting intervention using BRB. The maximum top displacement registered for the retrofitted frame under earthquake excitation coincides with the target displacement obtained in accordance with the design procedure. The introduction of buckling-restrained braces enhances the earthquake resistance of the steel frame, providing significant energy dissipation and the stiffness needed to satisfy structural drift limits.

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