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Book Seismic Retrofit of Non ductile RC Frames Using Friction Dampers

Download or read book Seismic Retrofit of Non ductile RC Frames Using Friction Dampers written by Rajesh Shankar Rao and published by . This book was released on 1996 with total page 602 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Seismic Analysis Behavior and Retrofit of Non ductile Reinforced Concrete Frame Buildings with Viscoelastic Dampers

Download or read book Seismic Analysis Behavior and Retrofit of Non ductile Reinforced Concrete Frame Buildings with Viscoelastic Dampers written by Chih-Ping Fan and published by . This book was released on 1998 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Many reinforced concrete (RC)) frame buildings constructed in the United States during the 1950s through 1970s were designed for gravity loads only using the non-seismic design provisions of the ACI-318 building code and ACI-315 detailing manual. The seismic performance of these RC frame buildings is unsatisfactory with brittle (non-ductile) failure modes that are controlled by poor reinforcing details including reinforcement with inadequate anchorage details, and joints and critical regions with light confinement and inadequate shear reinforcement. In particular, the columns of these non-ductile frame buildings have inadequate strength and ductility. Therefore, these buildings require retrofit to provide good seismic performance.

Book Proceedings

Download or read book Proceedings written by and published by . This book was released on 1995 with total page 188 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Technical Report

Download or read book Technical Report written by and published by . This book was released on 1987 with total page 210 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Seismic Retrofit of Reinforced Concrete Frames with Diagonal Prestressing Cables

Download or read book Seismic Retrofit of Reinforced Concrete Frames with Diagonal Prestressing Cables written by Ali Molaei and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A large number of building inventory in Canada and elsewhere in the world consists of non-ductile reinforced concrete frames, with or without masonry infill panels. These structures suffer damage when seismic force demands are higher than their force capacities. Therefore, seismic retrofitting of such frame buildings for drift control remains to be a viable option for improved building performance. A retrofit methodology has been developed in the current research project, which involves diagonal bracing of frames with prestressing strands. An experimental research project has been conducted to assess the effectiveness of diagonal prestressing in non-ductile reinforced concrete frame buildings. The experimental program consists of two large-scale single-bay single-storey reinforced concrete frames, with a height of 3.0m and a span length of 3.5 m. The frames were designed and built to reflect the 1960's practice in Canada, without the seismic requirements of current building codes, and hence are seismically deficient. They were retrofitted with diagonally placed prestressing strands, having two different areas of steel, prestressed to 40% of the strand capacity. One of the frames was retested after the failure of the strands, with a new set of strands without any prestressing, forming the third test. The results indicate that lateral bracing reinforced concrete frames with high-strength prestressing strands is an effective strategy for controlling lateral drift and hence potential damage in buildings during strong earthquakes. Prestressing of the strands increases initial stiffness, as compared to non-prestressed cables, and provide superior performance. The area of diagonally placed steel (including the number of strands) and the level of initial prestressing depend on the required level of upgrade in the building in terms of seismic force requirements. The design procedure recommended in this thesis may be employed for implementing the technology. The thesis presents the details of the experimental program, and the test results. It also provides analytical verification of the approach, with a step-by-step design procedure.

Book RC Frames Under Earthquake Loading

Download or read book RC Frames Under Earthquake Loading written by Comité euro-international du béton and published by Thomas Telford. This book was released on 1996 with total page 328 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report examines the behaviour of individual frame members subjected to the cyclic actions arising in seismically loaded frames i.e. slender flexure-dominated beams, short columns and beam-column joints. The report also considers global inelastic frame behaviour and its modelling, and the peculiarities of the behaviour of masonry-filled frames.

Book Technical Report

Download or read book Technical Report written by and published by . This book was released on 2008 with total page 348 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Seismic Retrofit of Unreinforced Masonry Infills in Non ductile Reinforced Concrete Frames Using Engineered Cementitious Composites

Download or read book Seismic Retrofit of Unreinforced Masonry Infills in Non ductile Reinforced Concrete Frames Using Engineered Cementitious Composites written by Marios Kyriakides and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Masonry infills in non-ductile reinforced concrete frames can be found in many places around the world, such as the western United States, China, and in countries of the Mediterranean region. There is strong laboratory and field evidence that masonry infills can improve the performance of reinforced concrete structures, as demonstrated in the 1994 Northridge earthquake. However, many masonry-infilled reinforced concrete buildings suffered catastrophic failures in recent earthquakes such as in the 1999 Kocaeli earthquake in Turkey and the 2008 Sichuan earthquake in China, causing the death of hundreds of people and affecting the lives of millions. A new seismic retrofit technique specifically for unreinforced masonry infills in non-ductile reinforced concrete frames has been developed. The technique uses a sprayable, ductile fiber-reinforced cement based material referred to as Engineered Cementitious Composites, or ECC. Small-scale component experiments including compression tests of masonry prisms and flexural tests of masonry beams retrofitted with different ECC retrofit schemes were conducted to investigate the impact of the retrofit on the performance of masonry in terms of strength, stiffness and ductility. The findings of the small-scale component experiments were used for the development of the ECC retrofit design. Four 1/5-scale masonry infilled non-ductile reinforced frames - one with an unretrofitted masonry wall and three with retrofitted masonry walls - were subjected to quasi-static, in-plane cyclic loading to validate the retrofit design. It was found that when a thin layer of ductile cement-based retrofit is applied to the masonry wall and properly tied into the concrete frame, the deformation capacity of the infilled frame is increased 10 times through a rocking motion. In collaboration with researchers from The University of Colorado, at Boulder and The University of California, San Diego, the retrofit design was evaluated through a quasi-static, in-plane cyclic test of a 2/3-scale masonry infilled non-ductile reinforced concrete frame and a dynamic shake-table test of a 2/3-scale, three-story, two-bay masonry infilled non-ductile reinforced concrete frame. These tests demonstrated that the ECC retrofit can significantly improve the performance of this type of structure under cyclic loads and seismic excitation. Existing analytical models for the prediction of the lateral strength and failure mode of masonry infilled reinforced concrete frames subjected to in-plane lateral load are evaluated through a limit analysis method. New analytical models for such structures with ECC retrofitted masonry walls are proposed. Two-dimensional non-linear finite element analyses using two different micro-modeling approaches are used to simulate unreinforced masonry beams retrofitted with a thin layer of ECC under four-point bending. In a detailed approach each material is modeled independently and in a simplified approach, expanded brick units with zero thickness mortar elements are used. The adequacy of these models to capture the experimental response of ECC strengthened masonry beams under out-of-plane bending is examined. The impact of the amount and location of reinforcement in the ECC layer, and of the use of anchors as a method of improvement of the bond between the ECC layer and the masonry surface is also examined through simulation. Two-dimensional non-linear finite element analyses are conducted to asses the ability of various smeared and discrete crack modeling approaches in a commercial finite element program for capturing the response of masonry infilled non-ductile reinforced concrete frames. A methodology for simulating this type of structures with ECC retrofitted walls in two dimensions is also presented.

Book Probabilistic Assessment of Non ductile Reinforced Concrete Frames Susceptible to Mid America Ground Motions

Download or read book Probabilistic Assessment of Non ductile Reinforced Concrete Frames Susceptible to Mid America Ground Motions written by Ozan Cem Celik and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The infrequent nature of earthquakes in the Central and Eastern United States (CEUS), and the fact that none with intensity comparable to the New Madrid sequence of 1811--12 or the Charleston earthquake of 1886 has occurred in the past century, have caused the earthquake hazard in the region to be ignored until quite recently. The seismic performance of reinforced concrete (RC) frames in the CEUS, which have primarily been designed for gravity load effects, is expected to be deficient when subjected to earthquakes that are judged, in recent seismological research, as being plausible in the New Madrid Seismic Zone (NMSZ). The objective of this study is to develop a set of probability-based tools for efficient uncertainty analysis and seismic vulnerability and risk assessment of such gravity load designed (GLD) RC frames and to use these tools in evaluating the seismic vulnerability of RC frames that are representative of the building inventory in Memphis, TN -- the largest population center close to the NMSZ. Synthetic earthquake ground motions for the CEUS that are available from two different Mid-America Earthquake (MAE) Center projects were used in the finite element-based simulations for determining the seismic demand on the GLD RC frames by nonlinear time history analysis (NTHA). A beam-column joint model was developed to address the deficiencies in the joints of GLD frames and was incorporated in the finite element structural models. Seismic fragilities were derived for low-, mid-, and high-rise GLD RC frames. Various sources of uncertainty were propagated through the analysis, and their significance for fragility assessment was examined. These fragilities were used to evaluate the vulnerability of the RC frame inventory in Memphis, TN with regard to performance-based design objectives, defined in terms of performance levels associated with reference earthquake hazard levels. This performance appraisal indicated that GLD RC frames do not meet the life safety and collapse prevention performance objectives that are found in recent building codes and guidelines for performance-based earthquake engineering.