Browse - Earthquake Spectra

Keyword
DOI
Citation
Advanced

Search Content Type

article doi:

Citation:

Home
Browse
About
Authors
Email Alerts
Scitation

SECTION LISTING

Reinforced Concrete Structures
Precast Concrete Structures
Steel Structures
Masonry Structures and Masonry Infill Walls
Foundations

BROWSE VOLUMES

Year Range:

2012

Volume 28

2011

Volume 27

2010

Volume 26

2009

Volume 25

2008

Volume 24

2007

Volume 23

2006

Volume 22

2005

Volume 21

2004

Volume 20

2003

Volume 19

2002

Volume 18

2001

Volume 17

2000

Volume 16

1999

Volume 15

1998

Volume 14

1997

Volume 13

1996

Volume 12

Issue 4 | November 1996 | pp. 645-942

Issue 3 | August 1996 | pp. 371-638

Issue 2 | May 1996 | pp. 185-365

Issue 1 | February 1996 | pp. 1-180

Issue S1 | January 1996 | pp. xv-278

1995

Volume 11

1994

Volume 10

1993

Volume 9

1992

Volume 8

1991

Volume 7

1990

Volume 6

1989

Volume 5

1988

Volume 4

1987

Volume 3

1986

Volume 2

1985

Volume 1

Select this Article		Seismic Design and Testing of an RC Slab‐Column Frame Strengthened by Steel Bracing Adnan C. Masri and Subhash C. Goel, M.EERI Earthquake Spectra 12, pp. 645-666 (1996); doi:http://dx.doi.org/10.1193/1.1585904 \| Cited 3 times Online Publication Date: 29 April 2003 Full Text: \| Download PDF
	+ -	Show Abstract This study is concerned with developing a rational design procedure for use of ductile steel bracing for strengthening existing seismically “weak” RC slab‐column building structures. A one‐third scale, two‐bay, two‐story RC slab‐column frame model was selected to represent existing seismically inadequate structures of its type. The design procedure, construction and test results of the steel bracing system for strengthening the RC frame are presented in this paper. The strengthened frame was subjected to a combination of gravity and cyclic lateral loads up to 2% overall frame drifts. The behavior of the strengthened frame improved dramatically over that of the bare RC frame. A maximum 2.75% drift in the first story was reached which is highly probable during severe earthquake motions.

Select this Article		Lateral Response of Older Flat Slab Frames and the Economic Effect on Retrofit Laurel Dovich, M.EERI and James K. Wight, M.EERI Earthquake Spectra 12, pp. 667-691 (1996); doi:http://dx.doi.org/10.1193/1.1585905 Online Publication Date: 29 April 2003 Full Text: \| Download PDF
	+ -	Show Abstract Seismic retrofit schemes for older flat slab frames are commonly designed to carry the full design lateral loads, based on the assumption that the existing slab‐column frame has low lateral stiffness and may fail in a brittle manner during earthquake loading. An experimental study was conducted to probe the actual response of a two story by two bay frame, and two isolated connection specimens, under cyclic lateral load reversals. The behavior observed indicated that for reasonable gravity loads, the lateral load response of these older slab‐column frames is more ductile than anticipated. Therefore, structural engineers should be encouraged to utilize the strength and stiffness of the existing slab‐column frame when designing a seismic retrofit system for the frame. Such a design will be less conservative, and thus less expensive, than is common in current design practice.

Select this Article		Retrofit of Concrete Columns with Inadequate Lap Splices by the Use of Rectangular Steel Jackets Riyad S. Aboutaha, M.EERI, Michael D. Engelhardt, M.EERI, James O. Jirsa, M.EERI, and Michael E. Kreger, M.EERI Earthquake Spectra 12, pp. 693-714 (1996); doi:http://dx.doi.org/10.1193/1.1585906 \| Cited 3 times Online Publication Date: 29 April 2003 Full Text: \| Download PDF
	+ -	Show Abstract This paper describes an experimental research program on the use of rectangular steel jackets for seismic retrofit of non‐ductile reinforced concrete frame columns. Eleven large scale columns were tested to examine the effectiveness of various types of steel jackets for improving the ductility and strength of columns with an inadequate lap splice in the longitudinal reinforcement. Response of the columns before and after being strengthened with steel jackets was examined. Several types of steel jackets were investigated, including rectangular solid steel jackets with and without adhesive anchor bolts. The test results indicate that a thin rectangular steel jacket combined with adhesive anchor bolts can be a highly effective retrofit measure for reinforced concrete columns with an inadequate lap splice. Design guidelines for the use of rectangular steel jackets as a seismic retrofit for non‐ductile reinforced concrete columns are presented.

Select this Article		Seismic Evaluation of Existing Reinforced Concrete Building Columns Abraham C. Lynn, M.EERI, Jack P. Moehle, M.EERI, Stephen A. Mahin, M.EERI, and William T. Holmes, M.EERI Earthquake Spectra 12, pp. 715-739 (1996); doi:http://dx.doi.org/10.1193/1.1585907 \| Cited 11 times Online Publication Date: 29 April 2003 Full Text: \| Download PDF
	+ -	Show Abstract Past earthquakes have emphasized the vulnerability of reinforced concrete columns having details typical of those built before the mid‐1970's. These columns are susceptible to axial‐flexural, shear, and bond failures, which subsequently may lead to severe damage or collapse of the building. Research was undertaken to investigate the lateral and vertical load‐resisting behavior of reinforced concrete columns typical of pre‐1970's construction. Eight full‐scale specimens were constructed and were loaded with constant axial load and increasing cyclic lateral displacement increments until failure. Test data are presented and compared with behavior estimated by using various evaluation methods.

Select this Article		Retrofit of Non‐Ductile Moment‐Resisting Frames Using Precast Infill Wall Panels Robert J. Frosch, M.EERI, Wanzhi Li, James O. Jirsa, M.EERI, and Michael E. Kreger, M.EERI Earthquake Spectra 12, pp. 741-760 (1996); doi:http://dx.doi.org/10.1193/1.1585908 \| Cited 3 times Online Publication Date: 29 April 2003 Full Text: \| Download PDF
	+ -	Show Abstract Many existing reinforced concrete moment‐resisting frames located in seismic zones lack strength and ductility. One approach for correcting these deficiencies is the construction of infill walls to strengthen and stiffen the structure. Cast‐in‐place construction is often used; however, there are conditions where cost, time constraints, or limiting disruptions to building operations may dictate other solutions. One possible modification is the use of infill walls constructed of precast concrete panels. A precast infill wall system eliminates the need for large formwork during construction. Elimination or reduction of connection hardware between precast panels or between panels and the existing frame element can provide additional efficiency. Problems associated with casting large quantities of concrete in an existing building are eliminated. Construction time and inconvenience to occupants may be reduced along with the costs. The precast system has the potential of reducing the overall costs of rehabilitating existing structures.

SECTION LISTING

BROWSE VOLUMES

November 1996

Volume 12, Issue 4, pp. 645-942

Your Recent History

Recently Viewed

Find articles by AUTHORNAME

Select this Article		Preface James O. Jirsa Earthquake Spectra 12, pp. v-vii (1996); doi:http://dx.doi.org/10.1193/1.1585903 Online Publication Date: 29 April 2003 Full Text: \| Download PDF
		Abstract Unavailable

Select this Article		Seismic Rehabilitation of Reinforced Concrete Beam‐Column Connections A. Ghobarah, M.EERI, Tarek. S. Aziz, and Ashraf Biddah Earthquake Spectra 12, pp. 761-780 (1996); doi:http://dx.doi.org/10.1193/1.1585909 \| Cited 4 times Online Publication Date: 29 April 2003 Full Text: \| Download PDF
	+ -	Show Abstract As building codes are updated, some of the existing important structures may fall short of complying with current standards even though they may have been properly designed and constructed according to earlier codes. Many existing structures may be inadequate and may pose severe risk during seismic events. Rehabilitation measures to upgrade the capacity of these structures can be performed at some point in their useful lives especially when located in seismically active zones. A new method for improving the seismic performance of existing reinforced concrete structures is by jacketing the deficient connections using corrugated steel jackets. An experimental program was conducted to evaluate this method of rehabilitation. Corrugated steel jacketing addresses the particular weakness that is often found in existing reinforced concrete structures, namely the lack of sufficient shear reinforcement and the required confining reinforcement within the joints and in adjoining beams and columns. The performance of four reinforced concrete connections was determined experimentally. The test specimens include one connection representing existing structures, one designed according to current seismic codes and two rehabilitated connections. The test results showed satisfactory performance at high cyclic load levels and significant increase in the shear capacity and ductility of connections rehabilitated with corrugated steel jackets.

Select this Article		Measured Response of Roof Diaphragms and Wall Panels in Tilt‐Up Systems Subjected to Cyclic Loading Fernando S. Fonseca, M.EERI, Sharon L. Wood, M.EERI, and Neil M. Hawkins, M.EERI Earthquake Spectra 12, pp. 783-802 (1996); doi:http://dx.doi.org/10.1193/1.1585910 Online Publication Date: 29 April 2003 Full Text: \| Download PDF
	+ -	Show Abstract An experimental program was developed to study the strength and deformation capacity of tilt‐up structures with plywood roof diaphragms. Two models of tilt‐up systems were constructed and tested in the laboratory. The structures were representative of one‐story warehouse construction in the western U.S. The overall dimensions of the two test specimens were the same; however, the number and distribution of reinforced concrete wall panels were varied. Each specimen was subjected to a series of lateral load reversals. Two aspects of the measured response of the test specimens are discussed in this paper: the in‐plane displacements of the plywood roof diaphragm and the transverse response of the perimeter wall panels. The wall panels experienced nearly rigid‐body rotation during the entire testing series, and the observed nonlinear response of the test specimens may be attributed to the inherent flexibility of the plywood diaphragm.

Select this Article		Expected Seismic Behavior of Older Steel Structures Charles W. Roeder, M.EERI, Roberto Leon, M.EERI, and F. Robert Preece, M.EERI Earthquake Spectra 12, pp. 805-821 (1996); doi:http://dx.doi.org/10.1193/1.1585911 Online Publication Date: 29 April 2003 Full Text: \| Download PDF
	+ -	Show Abstract Older steel structures frequently require seismic rehabilitation, but the inelastic seismic behavior of these older structures is not well understood. A joint research study between the U. of Washington, U. of Minnesota, and Preece/Goudie and Associates examined this behavior. The study included experimental and analytical studies, and this paper is an overview of the research and the more important research results. It provides a concise summary of the rather extensive research program, and the research results are correlated to real structural behavior. This correlation includes evaluation and comparison with behavior observed during past earthquakes. The paper will help the reader understand the performance of the total structural system will provide valuable insight for engineers starting a repair or retrofit project, and it will isolate potential problem areas to be considered in rehabilitation projects.

Select this Article		Out‐of‐Plane Strength of Unreinforced Masonry Infill Panels Daniel P. Abrams, M.EERI, Richard Angel, and Joseph Uzarski, M.EERI Earthquake Spectra 12, pp. 825-844 (1996); doi:http://dx.doi.org/10.1193/1.1585912 \| Cited 4 times Online Publication Date: 29 April 2003 Full Text: \| Download PDF
	+ -	Show Abstract Simple procedures are presented for estimating out‐of‐plane strength of unreinforced masonry infill panels. The procedures are based on an experimental study and subsequent development of an analytical model, which are described as a preface to derivation of a simple and approximate expression for estimating out‐of‐plane strength of a general class of infill panels. An example is given illustrating application of the proposed guideline.

Select this Article		Seismic Strengthening of Unreinforced Masonry Piers with Steel Elements Durgesh C. Rai, M.EERI and Subhash C. Goel, M.EERI Earthquake Spectra 12, pp. 845-862 (1996); doi:http://dx.doi.org/10.1193/1.1585913 \| Cited 3 times Online Publication Date: 29 April 2003 Full Text: \| Download PDF
	+ -	Show Abstract The system of wall piers and spandrels, created by openings, largely controls the inplane lateral resistance of the wall. For the “rocking‐critical” masonry wall piers, the overall hysteretic behavior can be significantly improved by installing a steel framing system consisting of vertical and horizontal elements around the wall — without any braces. Vertical elements provide the necessary hold‐down forces to stabilize the rocking piers. The stabilized piers “rocked” through a number of cycles of large displacements (up to 2.5%) without crumbling or shattering, displaying a ductile response. The strengthened system has excellent strength, stiffness and ductility, despite the brittleness of the masonry because of considerable load sharing between the existing masonry and the added steel elements. FE analyses predicted the envelope response of the rocking piers accurately. A simple mechanics based model was developed to predict the load‐deflection behavior of a stabilized rocking pier which can be used to design the strengthening system more rationally.

Select this Article		Seismic Rehabilitation of Infilled Non‐Ductile Frame Buildings Using Post‐Tensioned Steel Braces Amador Terán‐Gilmore, M.EERI, Vitelmo V. Bertero, M.EERI, and Nabih F.G. Youssef, M.EERI Earthquake Spectra 12, pp. 863-882 (1996); doi:http://dx.doi.org/10.1193/1.1585914 \| Cited 1 time Online Publication Date: 29 April 2003 Full Text: \| Download PDF
	+ -	Show Abstract In recent years, it has been shown that the seismic performance of existing buildings can be enhanced considerably by bracing them with post‐tensioned rods or cables. This upgrading technique has several advantages, which include architectural versatility, low cost and fast construction. Furthermore, it does not add a significant mass to the existing building. The objectives of the present paper are to: investigate the use of post‐tensioned steel bracing for seismic retrofit of non‐ductile reinforced concrete frames with unreinforced masonry infills, discuss some of the issues that need to be addressed in the design of the rehabilitated building, assess the advantages of this rehabilitation technique by studying the seismic performance of an infilled non‐ductile frame building before and after it has been upgraded with post‐tensioned braces, and propose research recommendations.

Select this Article		Some Retrofit Options for the Seismic Upgrading of Old Low‐Rise School Buildings in Mexico Arturo Tena‐Colunga, M.EERI Earthquake Spectra 12, pp. 883-902 (1996); doi:http://dx.doi.org/10.1193/1.1585915 \| Cited 1 time Online Publication Date: 29 April 2003 Full Text: \| Download PDF
	+ -	Show Abstract An analytical study regarding the seismic upgrading of typical 60's and 70's designs for public school buildings in Mexico is presented. Some schools with these designs were moderately damaged during the 1985 Michoacán Earthquake in Mexico City. The damage was primarily observed in their longitudinal direction where existing slender RC columns have their weak axis. In addition, these columns are confined and shortened by masonry walls that do not run all the story height. These walls are supposed to be non‐structural components, however, they experienced shear cracking during the quake due to the distress of the confined columns. Some school buildings were retrofitted after the Michoacán Earthquake adding post‐tensioned bracing systems composed of prestressed high‐slenderness steel strands (tension‐only bracing systems), a retrofit option that is economical. In fact, there is an interest on assessing the effectiveness of this retrofit scheme in other regions with different soil conditions, as for example, the hard soils of the Mexican Pacific Coast. Therefore, the post‐tensioning retrofit scheme used for the school buildings in Mexico City was also evaluated for hypothetical locations in the Mexican Pacific Coast. Another option that seems economical for the seismic retrofit of old school buildings in the Mexican Pacific Coast is the use of base isolators. Then, a retrofit plan using lead‐rubber bearings was also evaluated. Acceleration time‐histories recorded in the Mexican Pacific Coast during the 1985 Michoacán and the 1995 Manzanillo Earthquakes were used to assess the effectiveness of the studied retrofit schemes. Records in Mexico City for the 1985 Michoacán Earthquake and postulated ground motions for a M_s = 8.1 earthquake in Mexico City were also used. The effectiveness of each retrofit scheme is discussed through the comparison of the seismic behavior of original and retrofit structures using a comprehensive set of analyses.

Select this Article		Repair and Retrofit of Unreinforced Masonry Structures Teymour Manzouri, Michael P. Schuller, P. Benson Shing, M.EERI, and Bernard Amadei Earthquake Spectra 12, pp. 903-922 (1996); doi:http://dx.doi.org/10.1193/1.1585916 \| Cited 2 times Online Publication Date: 29 April 2003 Full Text: \| Download PDF
	+ -	Show Abstract A comprehensive study was conducted to evaluate the efficacy of different repair and retrofit techniques for unreinforced masonry (URM) structures. The study was to identify suitable grouting materials and procedures for the repair and retrofit of URM structures, quantify the efficacy of different repair and retrofit techniques, and develop analysis tools to evaluate the performance of masonry structures before and after retrofit. To this end, a number of grouting materials and procedures were evaluated with material tests, masonry component tests and shear wall tests. The experimental results indicate that the strength and stiffness of damaged walls can be fully restored with grout injection. Furthermore, the strength and ductility of a URM wall can be greatly enhanced by the introduction of steel reinforcement.

Select this Article		The Role of Building Foundations in Seismic Retrofit Charles W. Roeder, M.EERI, Sunirmal Banerjee, Debbie R. Jung, and Sean K. Smith Earthquake Spectra 12, pp. 925-942 (1996); doi:http://dx.doi.org/10.1193/1.1585917 \| Cited 1 time Online Publication Date: 29 April 2003 Full Text: \| Download PDF
	+ -	Show Abstract Existing buildings which do not satisfy modern seismic design requirements may be rehabilitated economically by the addition of steel bracing or reinforced concrete shear walls. However, steel bracing and concrete shear walls can place severe demands on the building foundation, and the existing foundations are likely to be inadequate. Strengthening of existing foundations may be exceedingly expensive, and the cost of the foundation work may dominate the seismic retrofit effort. Several foundation retrofit strategies are described and discussed. These strategies are invariably expensive, and the engineer may be tempted to place the major investment into strengthening or stiffening the structure with minimal work on the foundation. This concept may lead to increased potential for uplift and temporary overload of footings. In some cases this practice may have beneficial effect regarding the overall seismic response of the structure. It may reduce both seismic forces and maximum displacements experienced by the structure. The reduced foundation retrofit is unlikely to increase the collapse potential or life‐safety risks of the building, while the structural retrofit should significantly improve the life‐safety concerns. However, the combination of structural rehabilitation combined with minimal foundation rehabilitation are likely to increase the potential damage and economic loss during an earthquake.