Seismic retrofit of large-scale interior RC beam-column-slab joints after standard fire using steel haunch system

In original seismic design of the Seto-Ohashi Bridges, an inland near-field earthquake was not considered. And there is concern that large-scale earthquakes would occur in the near future. Therefore seismic retrofit for truss bridges of the Seto-Ohashi Bridges has started. In the seismic retrofit design for the truss bridges, it was decided that seismic response of overall bridge was reduced firstly and the truss members were strengthened by additional stiffeners secondly. The stiffeners were attached to the truss members by bolting, because it was difficult to ensure quality of field welding. As inner surface of the closed box-section truss members has no coating, drilling bolt holes in the members was thought to increase the probability of corrosion of the members. Therefore it was decided to apply airtightness measures for the inside of the closed box-section members after their drying.

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Retrofit of Concrete Columns with Inadequate Lap Splices by the Use of Rectangular Steel Jackets

Earthquake Spectra ◽

10.1193/1.1585906 ◽

1996 ◽

Vol 12 (4) ◽

pp. 693-714 ◽

Cited By ~ 36

Author(s):

Riyad S. Aboutaha ◽

Michael D. Engelhardt ◽

James O. Jirsa ◽

Michael E. Kreger

Keyword(s):

Reinforced Concrete ◽

Large Scale ◽

Concrete Columns ◽

Seismic Retrofit ◽

Design Guidelines ◽

Reinforced Concrete Frame ◽

Reinforced Concrete Columns ◽

Lap Splice ◽

Concrete Frame ◽

Anchor Bolts

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.

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Seismic Retrofit of Large-Scale Reinforced Concrete Columns by Prestressed High-Strength Metal Strips

Structures Congress 2009 ◽

10.1061/41031(341)313 ◽

2009 ◽

Cited By ~ 3

Author(s):

Hasan A. Moghaddam ◽

Maysam Samadi

Keyword(s):

Reinforced Concrete ◽

Large Scale ◽

High Strength ◽

Concrete Columns ◽

Seismic Retrofit ◽

Reinforced Concrete Columns

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Experimental investigations on the load bearing behaviour of an innovative prestressed composite floor system in fire

Proceedings 12th international conference on Advances in Steel-Concrete Composite Structures - ASCCS 2018 ◽

10.4995/asccs2018.2018.7020 ◽

2018 ◽

Author(s):

Patrick Meyer ◽

Peter Schaumann ◽

Martin Mensinger ◽

Suet Kwan Koh

Keyword(s):

Fire Resistance ◽

Large Scale ◽

Concrete Slab ◽

Experimental Investigations ◽

Load Bearing ◽

Natural Fire ◽

Fire Scenario ◽

Standard Fire ◽

Hollow Space ◽

Floor System

In Germany, regulations for hollow spaces in slab systems require 30 minutes standard fire resistance of the load-bearing steel construction. Within a current national research project a natural fire scenario for the hollow space was developed based on realistic fire loads and ventilation conditions in the hollow space. Assuming this realistic fire scenario in the hollow space, two large scale tests on an innovative composite floor system were performed to evaluate the influence on the load bearing behaviour of the floor system. The integrated and sustainable composite floor system consists of a prestressed concrete slab, an unprotected, bisected hot rolled I-profile with composite dowels either in puzzle or clothoidal shape, and removable floor panels on the top of the I-profile. This floor system ensures the opportunity to adjust the technical building installations in accordance with the use of the building. This integrated and sustainable composite floor system was developed in several research projects. The standard fire resistance R90 for the fire scenario below the slab system has already been proven successfully. In this paper, experimental investigations regarding the heating and load bearing behaviour of the innovative composite floor system under the newly developed natural fire scenario of hollow spaces are presented. In doing so, the special test set-up to realise the fire tests for the fire scenario hollow space will be described in detail. After the fire scenario for the hollow space, the specimen was subjected to the ISO standard fire curve to establish the failure temperature of the unprotected I-profile. In addition to the temperature development and the load bearing behaviour inside the innovative floor during the heating phase, the cooling phase and the influence of a web opening on the load bearing behaviour will be discussed.

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