Mete Sozen

• Purdue University West Lafayette

Structural engineering for earthquake resistance is undergoing a major revision in its approach toward the fulfillment of seismic safety and utilitarian serviceability in design. Rather than sticking to the established precepts of prescriptive design rules, design has turned toward the achievement of specific results through procedures that are tai...

Flat plates were designed and built in the early twentieth century without sensitivity to earthquake demands. The test reported was made to study the lateral stiffness, strength, and drift limit in one direction of a three-story, two-bay, full-scale reinforced concrete flat-plate building proportioned to resist gravity loading only. The focus of th...

An expression to estimate the unit shear strength of reinforced concrete columns is developed and calibrated using results from 62 tests on reinforced concrete members with rectangular cross sections. The effects of longitudinal reinforcement, transverse reinforcement, and axial load on shear strength are estimated with a simple formulation based o...

Encouraging creative uses of reinforced concrete, Principles of Reinforced Concrete Design draws a clear distinction between fundamentals and professional consensus. This text presents a mixture of fundamentals along with practical methods. It provides the fundamental concepts required for designing reinforced concrete (RC) structures, emphasizing...

This paper presents an experimental study of two full-scale reinforced concrete (RC) beam-column assemblies under a column removal scenario. The assemblies represent part of the exterior moment-resisting frames of two 10-story RC frame buildings: one designed for Seismic Design Category C (SDC C), and the other for SDC D. Intermediate moment frames...

The possibility of a violent ground motion in a population center poses multiple threats to the safety and continuity of society. It has to be met on multiple planes including the political and the economical. It is not an exaggeration to claim that the construction trades in many parts of the world understood the threat only in twentieth century....

The overall earthquake response of flat-plate structures depends on the hysteretic properties of the slab-column connection. The current understanding of the behavior is based largely on the tests of small-scale isolated slab-column assemblies. The results obtained contain a wide range of maximum drift ratios and failure modes that create uncertain...

This report was prepared as an account of work sponsored by the United States Government. Neither the United States nor the Energy Research and Development Administration, nor any of their employees, nor any of their contractors, subcontractors, or their employees, makes any warranty, express or implied, or assumes any legal liability or responsibi...

Engineering consensus documents in the U.S. on proportioning of reinforced concrete slabs went through creative and contradictory transformations starting in 1900's until a compromise was reached between mechanics and practice as a result of the Investigation of Multiple-Panel Floor Slabs carried out in Talbot Laboratory of the University of Illino...

This report presents an experimental and computational study of two reinforced concrete beam-column assemblies, each comprising three columns and two beams. The two beam-column assemblies represent portions of the structural framing system of two ten-story reinforced concrete frame buildings. One building was designed for Seismic Design Category C...

This paper mainly discusses the derivation and usage of simplified analysis model of circular concrete-filled steel tube specimen under lateral impact. At first, the robust software, LS-DYNA, is employed in this paper to simulate a test of circular concrete-filled steel tube (CFT) specimen under drop impact carried out by Li (2007). The numerical s...

A specific type of structural damage that would benefit from remote sensing is discussed and a solution is suggested.

The behavior of the World Trade Center Tower 1 on September 11, 2001 is studied in light of experimental data on the effect of elevated temperature on mechanical properties of structural steel. It is concluded that the damage inflicted by aircraft impact on the insulation of the core framing was the dominant factor in the collapse of the structure.

Several school buildings were surveyed in the disaster areas of the Marmara (17 August 1999, M w=7.4), Düzce (12 November 1999, M w=7.2), and Bingöl (1 May 2003, M w=6.4) earthquakes in Turkey. Among them, 21 reinforced concrete buildings were found to have an identical floor plan. Lateral load resisting structural system consisted of reinforced co...

The earthquake risk that Istanbul, the City of Domes, sustains has been investigated by many experienced and knowledgeable scientists and engineers ad infinitum (examples are Griffiths et al. 2007 and Parsons, 2004). Realistically, there is no room left for another opinion. Accordingly, the following text has been written appropriately in the shado...

Istanbul, a 2500-year old city, is under threat of a devastating earthquake. Reflecting past experience a very high probability of occurrence has been postulated for an M7 or larger earthquake during the next quarter century. The Metropolitan Municipality of Istanbul has committed itself to an ambitious program that targets urban rehabilitation par...

Following the 9/11 crash of an airliner at the Pentagon, the American Society of Civil Engineers established a team to study the response of the structure. The team reviewed available information on the structure, the crash loading, and the resulting damage. The team then analyzed the essential features of column response to impact, the residual fr...

A numerical constitutive model is developed to simulate the biaxial nonlinear flexural response of slender reinforced concrete members subjected to earthquake excitation. The model is tested using data from two types of experiments with reinforced concrete elements: (1) elements subjected to varying pseudo-static biaxial lateral loads and (2) eleme...

The manuscript contains a fictional discussion of the earthquake hazard Istanbul sustains and what may be done about it. Of all the fiction surrounding the issue, this may well be the only one that is admittedly so.

Results from 16 tests of reinforced concrete columns subjected to different displacement histories are presented. It is concluded that the drift capacity of a reinforced concrete column depends not only on the properties of the column and the applied axial load, but also on the displacement history. A numerical model to calculate drift capacity as...

The Pentagon was constructed between September 1941 and January 1943. A substantial renovation of the entire 6.6 million sq ft (610,000 sq m) facility began in 1999 and is scheduled for completion in 2010. On September 11, 2001, a hijacked commercial airliner crashed into the building. One-hundred eighty-nine persons were killed and a portion of th...

On September 11, 2001, an airliner was intentionally crashed into the Pentagon. It struck at the first elevated slab on the west wall, and slid approximately 310 ft (94.5 m) diagonally into the building. The force of the collision demolished numerous columns and the facade of the exterior wall, and induced damage to first-floor columns and the firs...

The devastation in the September 11, 2001 terrorist attack on the Pentagon was reduced by the building's resilient structural system. The continuity, redundancy, and energy-absorbing capacity embodied in this system should be incorporated in structures whose resistance to progressive collapse is important. Research should be conducted in the practi...

On September 11, 2001, the reinforced concrete structure of the Pentagon Building was able to resist, without collapse, the impact of a large commercial airliner despite the total loss of 26 columns and severe damage to 15 columns at the ground level. The ensuing fire and related fire-fighting activities led to the collapse of a portion of the buil...

An overview of fire damage sustained by the Pentagon structural elements in the September 11, 2001, terrorist attack is provided. The fire intensity in some compartments of the affected areas inside the Pentagon was approximated to be between those of the two standard fire exposures ASTM E119 and E1529, based on the observed fire damage and estimat...

Some engineers suggest that current seismic design provisions, both for new buildings and for strengthened existing buildings, can improve resistance to blast loads and progressive collapse. However, there have been few attempts to quantify such improvement. To begin analyzing this possible relationship between seismic detailing and blast and progr...

On February 7, 2003, a car bomb located inside the El Nogal building in Bogotá, Colombia, exploded causing extensive structural damage to the building. Two columns located less than 3 m from the vehicle suffered no appreciable damage. Bogotá is located in a moderate seismic zone and the code requirements for design of reinforced concrete structures...

A mathematical model is proposed for the calculation of settlement and rotation of shallow foundations under combined vertical load and bending moment. The main advantage of the suggested approach is the consideration of both: (i) the nonlinear nature of the problem and, (ii) the interaction effect between vertical load and bending moment and the c...

Simulations are essential tools in many fields of science and engineering. Researchers use them to crash-test automobiles before building them, to study the interaction between a hip implant and the femur, to evaluate and renovate medieval bridges, to assess the effectiveness of electronic circuit packaging, and to build virtual wind tunnels. This...

This paper describes the work of a team of researchers in computer graphics, geometric computing, and civil engineering to produce a visualization of the September 2001 attack on the Pentagon. The immediate motivation for the project was to understand the behavior of the building under the impact. The longer term motivation was to establish a path...

On September 11, 2001, a large commercial aircraft traveling at high speed crashed into the Pentagon. The aircraft and building debris pushed through the first story a distance of 310 feet into the building, inducing significant damage to the three outer rings of the west side of the Pentagon. The debris destroyed nearly 30 concrete columns and sig...

The Pentagon, the headquarters of the United States Department of Defense, was constructed between September 1941 and January 1943. A major renovation of the entire 6.6 million sq ft facility began in 1999 and is scheduled for completion in 2010. On September 11, 2001, a hijacked commercial airliner was intentionally crashed into the building in an...

On September 11, 2001, a large commercial aircraft traveling at high speed crashed into the Pentagon. The aircraft struck essentially at the second story slab, damaging columns on the first and second story and the slab of the second story in the outer ring of the structure. Then the aircraft debris slid under the second floor, 94.5 m (310 ft) into...

The impact of the aircraft destroyed or significantly impaired approximately 50 structural columns. The ensuing fire weakened a number of other structural elements. However, only a relatively small segment of the affected structure collapsed, approximately 20 minutes after impact. The collapse, fatalities, and damage were mitigated by the Pentagon'...

Two tall reinforced concrete chimneys, Stacks 25F-5 (115 m) and 36F-5 (107.5 m), were subjected to strong ground motion during the August 17, 1999, Marmara earthquake. Stack 25F-5 failed while Stack 36F-5 survived. Both stacks were designed in accordance with ACI 307-69. This study reports the earthquake parameters, the ground motion measured withi...

A series of experiments was carried out to investigate the behavior of columns with high-strength concrete subjected to shear reversals into the nonlinear range of response. The main experimental variables were loading history, axial load, and concrete strength. Columns measured 0.20 x 0.20 m (8 x 8 in.) in cross section and had shear span to depth...

The findings of the building performance study conducted following the September 11, 2001, terrorist attack on the Pentagon have far-reaching implications for the engineering and building professions-and for the general public as well. The building performance study team recommends that the features of the Pentagon's design that contributed to its...

During the twentieth century, consideration in design of drift response has moved with speed from a minor serviceability criterion to a central proportioning issue. It is suggested that the time is ripe for uncoupling the drift computation from calculated and often unrealistic lateral design forces and relating it directly to a design displacement...

The fault trace of the 12 November 1999 earthquake in theDzce-Bolu region in Anatolia crossed the alignment of a 2.4 kmviaduct in Kaynali that had been carefully surveyed. The builders of theviaduct, the ASTALDI-BAYINDIR Co., resurveyed the viaduct after theearthquake. We repeated the survey for approximately one kilometre of theeastern end of the...

At the time of this writing, three months after the 18 Aug. 1999 Kocaeli-Golcuk earthquake in northwest Turkey, the available data on the impact of the earthquake are still in a state of flux. The reported casualty count from the Kocaeli event has been slowly approaching 20,000 with almost twice as many reported injured. Over 100,000 residential un...

An appropriate formulation to determine the amount of transverse reinforcement for columns of reinforced concrete (RC) frames in seismic areas is presented. It is based on observations that suggested that the main function of transverse reinforcement is to confine the core subjected to a complex state of stress rather than simply resist shear or im...

A rationalization for ranking reinforced concrete frame buildings with masonry infill walls with regard to seismic vulnerability is presented. The method essentially requires only the dimensions of the structure as input, and is expressed in terms of where its attributes are located in a two-dimensional plot of masonry wall and column percentages....

From visual inspection and analysis of the damage that occurred in the Murrah Building as a result of a blast caused by a large truck bomb, it is shown that progressive collapse extended the damage beyond that caused directly by the blast. The type of damage that occurred and the resulting collapse of nearly half the building is consistent with wha...

The truck bombing of the Murrah Building caused significant damage to this structure. From the characteristics of the bomb crater, it was determined that the explosion yielded energy comparable to that from the detonation of 1,814 kg (4,000 lbs) of trinitrotoluene (TNT). The blast directly removed a principal exterior column, and the associated air...

In May 1995, the Federal Emergency Management Agency deployed a building performance assessment team composed of ASCE and federal government engineers to investigate damage caused by the malevolent bombing of the Alfred P. Murrah Federal Building. This paper describes the investigation of damage caused by the blast, the failure mechanism for the bu...

The truck bombing of the Murrah Building caused significant damage to this structure. From the characteristics of the bomb crater, the explosion yielded energy comparable to that froin the detonation of 4,000 Ib of trinitrotoluene (TNT). This directly removed a principal exterior column and the associated airblast failed two others. The airblast al...

This paper presents a simplified method of ranking reinforced concrete, low-rise, monolithic buildings according to their vulnerability to seismic damage. The ranking process requires only the dimensions of the structure. The process is tested using a group of buildings that suffered various levels of damage during the Erzincan earthquake of 1992....

For earthquake-resistant design of reinforced concrete structures, the shear force for frame elements is established on the basis of the proportions and flexural strength of the element according to the American Concrete Institute Standard 318-89 (1989), the Applied Technology Council Standard 3-06 (1989), and the Uniform Building Code, published i...

The Imperial County Services Building was severely damaged during the October 15th, 1979, Imperial Valley Earthquake. The vertical load carrying system and the structural systems used to resist lateral forces are described, and the response of the building is presented using reports of observed damage and acceleration histories measured with thirte...

The tragic experience of Mexico provides invaluable data for improving earthquake engineering construction and emergency response for the international community. To derive the optimum benefit for avoiding future catastrophes from this experience, certain projects ought to be implemented as soon as possible.

Three one-tenth scale models of the large-scale reinforced concrete structure tested in Tsukuba, Japan, were built and tested at the University of Illinois, Urbana. The small-scale models were subjected to scaled earthquake motions in one horizontal direction. The paper describes some of the dynamic response measurements and discusses the observed...

The response of interior reinforced concrete plate column connections in a laterally loaded structure is investigated. Nine specimens were tested, five statically and four dynamically to simulate earthquake loading. This paper describes results from statically tested specimens. Experimental variables include reinforcement ratio and amount of superi...

A simplified method is described for estimating lateral drift of reinforced concrete structures subjected to strong earthquake motion. The method is modeled after spectral-response analysis with simplifications based on observed characteristics of nonlinear dynamic response of reinforced concrete structures. Its application is limited to the types...

The Imperial County Services Building in El Centro, California, which was damaged by an earthquake on 15 October 1979 was studied to determine the specific causes of the failures. The studies included an experimental analysis of the structural system in the N-S direction. It was concluded that the critical column failures occurred almost at the end...

The object of this study was to compare the results of earthquake-simulation tests of I small-scale reinforced concrete structural models with those of pseudo-dynamic tests of a I large-scale reinforced concrete structure. Comparisons were made by analyzing both sets of I test results with the help of a SDOF model. To develop the analytical model,...

A simple analytical model is developed for the calculation of the seismic displacement history response of reinforced concrete frame and frame-wall structures. The computer cost for the model is approximately three precent of that for a MDOF system. A structure is idealized as a ″single-degree″ system consisting of a mass mounted on a rigid bar con...

An experimental study was undertaken to investigate the response to strong earthquakes of R/C structures having abrupt interruptions in adjacent story stiffness. Four structures (total weight of 2.29 meters) comprising two nine-story, three-bay frames or two frames and a wall which acted in parallel were tested. The first story was twice the height...

The object of the study was to attempt to simplify the nonlinear seismic analysis of reinforced concrete structures. The work consisted of two independent parts. One was to study the influence of calculated responses to hysteresis models used in the analysis, and to determine if satisfactory results can be obtained using less complicated models. Fo...

National Science Foundation Research Grant PFR 78-16318

This report documents the experimental work and presents the response data obtained in three earthquake simulation tests of a ten-story reinforced concrete frame. Changes in the dynamic properties of the test structure, such as apparent frequencies and equivalent damping, are discussed. Observed maximum lateral displacements are compared with those...

A small-scale, ten-story, reinforced concrete frame structure with relatively flexible lower stories was subjected successively to simulated earthquakes of increasing intensity on the University of Illinois Earthquake Simulator. The test structure comprised two frames situated opposite one another with strong axes parallel to a horizontal base moti...

Methods contained in the specifications of the Architectural Institute of Japan (AIJ) and the American Concrete Institute (ACI) for design of web reinforcement were studied to evaluate the relative probabilities of flexural and shear failures in reinforced concrete beans and columns proportioned on the basis of the AIJ and ACI methods. National Sci...

The Division of Highways. State of Illinois. U.S. Department of Commerce. Bureau of Public Roads.

This report describes a study aimed at developing an understanding of the response of reinforced concrete coupled wall systems to seismic loading. Five test structures (approximately one-twelfth scale) were subjected to one component of the earthquake base motion measured at El Centro, California (1940). The base motion were strong enough to cause...

A method is proposed to determine design forces for earthquake-resistant design of reinforced concrete structures. The method uses a modified linear model of the structure and recognizes the effect of energy dissipation in the nonlinear range of response. Thus, the designer is provided with a procedure, at the level of linear spectral response anal...

National Science Foundation Research Grant ATA 74 22962

The decay in shear strength of tied reinforced concrete columns during earthquake loading was investigated by subjecting 12 column specimens to several reversals of loading to deflections larger than the yield deflection. The principal variables of the test program were the axial load, the transverse reinforcement ratio, and the total deflection pe...

The report documents four series of tests investigating the effect of strain rate on the yield stresses of steel wire used as reinforcement in various models of reinforced concrete shear walls. It contains the results of 280 tensile tests on 7-inch-long specimens. One hundred forty tests were performed using No. 8 black annealed wire. Seventy of th...

Results of dynamic tests of reinforced concrete frames are used to illustrate the effects on dynamic response of changes in stiffness and energy dissipation capacity. It is shown that maximum inelastic response can be interpreted in terms of linearly elastic analysis by reference to a fictitious linear structure whose stiffness and damping characte...

The earthquake responses of a spirally reinforced concrete column carrying a concentrated mass and subjected to the simultaneous action (″ biaxial response″ ) of both horizontal components of normalized 1940 El Centro, 1962 Taft, and 1971 Pacoima Dam accelerograms were studied. Two different masses, corresponding to initial elastic periods of 0. 65...

The inelastic response of reinforced concrete multistory frames was investigated by subjecting small-scale one-bay three-story frames to a series of strong base motions simulating one horizontal component of representative earthquake acceleration records. It is concluded that strain-hardening characteristics of the reinforcing steel must be explici...

Study to investigate the mode of failure for a reinforced concrete column subjected to several reversals of loading to deflections larger than the yield deflection. A discussion of the type of failure observed during the testing of twelve column specimens is included. An analytical model, based on the material properties, was developed to simulate...

A series of small-scale models of prestressed concrete reactor vessels, with and without perforations in the end slab, were loaded to failure. All vessels failed in shear. The presence of penetrations did not decrease the strength of the end slab. The behavior of the vessels is described. Using a finite-element model, the stress conditions in the e...

The report contains the results of nine steel coupon tests and two analytical models to represent the measured stress-strain relationships. The objects of the study were specifically to investigate the stress-strain behavior of structural grade reinforcing steel under load reversals resulting in large strain increments representing the actual steel...

National Science Foundation Research Grant GI 29934

The experimental work included tests of small-scale one-bay three-story frames subjected to base motions simulating one horizontal component of representative earthquake-motion records. An analytical model was developed to calculate the dynamic response of a multistory frame for a given base motion, material properties and geometry of the structure...

The configuration of the vessels was that of a cylinder bounded by two flat slabs. The vessels were prestressed circumferentially and longitudinally and subjected to an internpressure. Vessels with solid end slabs and vessels with penetrations in the end slabs were studied. Six pressure vessels were tested. The only systematically varied variables...

The work described is part of an investigation of the resistance of reinforced concrete structures to earthquake motions with the overall objective of developing a realistic analytical model for the calculation of the response of reinforced concrete systems subjected to earthquakes. The investigation comprises the analyses and testing of simplified...

The National Science Foundation Research Grant GK-1894

Classification and description of damage are documented for 64 historical and monumental structures surveyed after the August 17 (Kocaeli) and November 12 (Düzce), 1999 earthquakes. The levels of damage recorded, construction type, and locations of the surveyed mosques and minarets are reported. Survey results indicated that the majority (70%) of t...

The expected performance of the Lawrence Livermore National Laboratory (LLNL) Plutonium Facility (Building 332) subjected to earthquake ground motion has been evaluated. Anticipated behavior of the building, glove boxes, ventilation system and other systems critical for containment of plutonium is described for three severe postulated earthquake ex...

Several sources have suggested that current seismic design provisions can improve blast and progressive collapse resistance. To examine this suggestion, the Federal Emergency Management Agency (FEMA) of the U.S. Department of Homeland Security (DHS) sponsored a study at the U.S. Army Engineer Research and Development Center (ERDC). The Alfred P. Mu...