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International Concrete Abstracts Portal

Showing 1-5 of 17 Abstracts search results

Document: 

SP211-07

Date: 

February 1, 2003

Author(s):

P. Paultre, J. Proulx, S. Mousseau, T. Prevoust, and C. Savard

Publication:

Symposium Papers

Volume:

211

Abstract:

Full-scale dynamic tests provide valuable information on the characteristics of building structures that can be used to calibrate finite element models, to rate modeling techniques, to determine damage levels, and to evaluate design and detailing requirements for seismic loading. These tests usually provide the most complete information about the dynamic properties of a structure, I.e., mass, stiffness, and modal damping. In the paper, the dynamic behavior of a two-story reinforced high-performance concrete building is evaluated by repeated pseudo-dynamic tests, during which increasing seismic loads are applied and with resulting greater levels of permanent damage to the structure. In order to monitor the level of damage, a series of successive forced-vibration tests are also carried out at each step of the process and are used to track changes in the key dynamic properties of the building. The paper presents the design of the test structure, the series of forced vibration and pseudo-dynamic tests, the evaluation of the dynamic characteristics of te undamaged structure prior to and after pseudo-dynamic tests, and the evaluation of the damages to the building.

DOI:

10.14359/12588


Document: 

SP211-11

Date: 

February 1, 2003

Author(s):

B. M. Shahrooz, G. Tunc, and J. T. Deason

Publication:

Symposium Papers

Volume:

211

Abstract:

A common connection between steel outrigger beams and reinforced concrete walls involves a shear tab welded onto a plate that is conncected to the wall through headed studs. Previous studies focused on behavior of headed studs have ignored a number of major issues, e.g., (a) cyclic behavior of studs under multiple loads was not studied, (b) the concrete around studs was not reinforced or the reinforcement did not represent what would commonly be present in wall boundary elements, and ( c) effects of cracking and yielding of reinforcement around headed studs were not included. To remedy these deficiencies and to develop seismic design guidelines for outrigger beam-wall connections, a coordinated experimental and analytical research program was conducted. Through a number of tests, involving a wall subassembly and an outrigger beam, the behavior of studs subjected to cyclic tension and constant gravity shear was examined, and a design methodology was developed to control the mode of failure. To further investigate the cyclic performance of outrigger beam-wall connections and to validate the design guidelines, two 1/4-scale walls with two outrigger beams were tested. The wall reinforcement details around the connection were selected according to the anticipated level of cracking and plastic hinge formation. The two outrigger connections were subjected to constant gravity loads and cyclic tensile forces, which were controlled as a function of the wall shear. This paper provides an overview of the experimental program, testing procedures, relevant test results, and design implications. The design methodology followed in this research resulted in connections that could develop and exceed the design forces despite extensive cracking and yielding of wall reinforcement around the headed studs. Presence of heavily confined wall boundary elements around headed studs increases the capacity. A simple method to account for strengthening effects of boundary elements was develped. This model could accurately assess the expected mode of failure and capacity of outrigger beam-wall connections. Test results indicate that the outrigger beam transfers the majority of diaphragm forces directly to the core wall, and participation of floor slab toward transferring the loads to the core wall is negligible. Therefore, floor diaphragm-wall connections can be based on simplle details, and designed to resist only gravity loads.

DOI:

10.14359/12592


Document: 

SP211-03

Date: 

February 1, 2003

Author(s):

C. MacDougall and F. M. Bartlett

Publication:

Symposium Papers

Volume:

211

Abstract:

A unique large-scale testing apparatus has been designed and built to facilitate the stressing and testing of 18.3 m lengths of steel prestressing strand. The strands are tested in a draped configuration to simulate the load and boundary conditions typical of an unbonded monostrand tendon in a post-tensioned concrete slab. Individual wires can be cut to simulate the occurrence of wire breaks due to corrosion. The apparatus consists of a steel wide flange beam with a parabolic profile plate that aligns the tendon in a draped configuration while providing access along the entire length for strain gauges. The overall length was selected, using mechanical models presented elsewhere, so that complete strain recovery could be observed in a wire with a break at the tendon mid-length. Other geometric variables were set to mimic the typical drape-to-span ratio of an unbonded monostrand tendon in a post-tensioned slab. Test results for intact 7-wire monostrand tendons correspond well to those predicted using the mathematical model of Machida and Durelli. Standard errors of 220 N and 133 microstrain were determined for the tendon load and wire strains, respectively. Thus, the apparatus can be used to accurately measure the mechanical response of unbonded 7-wire tendons.

DOI:

10.14359/12584


Document: 

SP211-02

Date: 

February 1, 2003

Author(s):

J. Pearson, G. Klein, M. A. Issa, and S. Kaderbeck

Publication:

Symposium Papers

Volume:

211

Abstract:

Wacker Drive in Chicago is a double-deck viaduct constructed along the Chicago River. Because of severe moisture-driven deterioration, the section of the elevated road between Randolph Street and Michigan Avenue are being reconstructed using a post-tensioned slab produced of high-performance concrete topped with a replaceable latex-modified concrete overlay. In order to verify the adequacy of the road way design, a full scale prototype was built and a test program was executed to evaluate the structural performance of the superstructure and its elements. Specifically, the following structural performance characteristics were evaluated: Positive and negative flexural strength Shear strength Live load stress range in concrete and post tensioning tendons Cracking at service load, overload and ultimate load Deflection at service load, overload and ultimate load Overlay bond strength and interaction between overlay and substrate Dynamic response This paper describes the prototype construction, analysis and testing.

DOI:

10.14359/12583


Document: 

SP211

Date: 

February 1, 2003

Author(s):

Editors: Mohsen A. Issa and Y.L. Mo

Publication:

Symposium Papers

Volume:

211

Abstract:

SP-211 This Symposium Publication contains 16 papers presented at the 2003 ACI Spring Convention in Vancouver, BC, Canada. To date, most structural tests are based on small-scale tests to verify the accuracy of analytical models. Small-scale tests can allow the mechanics (modes) of failure to be examined carefully at a fractional cost of full-scale testing. Full-scale tests render the realistic behavior of structures; however, they require large-scale testing facilities and an enormous amount of manpower in addition to being very expensive to set up and run. Whether large or small in scale, testing of structures and structural components are deemed vital in predicting field performance. This document demonstrates the effective use of various facilities to provide the realistic behavior of concrete structures through large-scale testing.

DOI:

10.14359/14021


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