Retrofitting and rehabilitation of fire damaged concrete. A separate issue is the foundation load path can be damaged by the fire event. This study explains the rehab process of fire damaged concrete buildings in three basic categories. It is aimed at giving a further contribution to understand the effect of fire with respect to the local aggregates, quenching methods and proposing an assessment methodology based on a suitable analytical procedure applied to. Moreover, care should be practiced to avoid cutting steel bars during concrete removal process. This publication is currently being revised by a concrete society. Fire damage, evaluation, ndt, and repair of concrete. Previously, the firedamaged concrete was repaired using the shotcrete and normal concrete. Test variables included the cfrp plate length and thickness of concrete cover over steel reinforcements. The residual strengths of the fire damaged columns were calculated. Assessment of firedamaged structures the concrete society. Before carrying out any repair it is necessary to determine the extent of the damage to the concrete and reinforcement. The material behaviour and traits of the constitutive parts i. Repair of firedamaged reinforced concrete members with.
From reconnaissance to advanced analysis venkatesh kodur a and ankit agrawala adepartment of civil and environmental engineering, michigan state university, usa outline 2 background to fire problem concrete structures under fire need for evaluating residual capacity approach for fire damage. The paper is concerned with the technical aspects of the appraisal and retrofitting process of fire damaged reinforced concrete structures. By bernard erlin download the pdf version of this article. Fire performance of earthquakedamaged reinforcedconcrete. One of the most important phenomena affecting the loadbearing capacity of these structures is the reduction in concrete strength at high temperature and. While concrete structures like the atlanta highway bridge are certainly resistive to fire damage, you must always consider the effects of any fire where concrete or masonry is exposed to high heat. Concrete has good fire resistance and concrete structures are capable of being repaired after a fire. Assessment of fire damage to a reinforced concrete. Fire is one of the most destructive accidental loads that a structure can be subjected during its lifetime. Fire damage, evaluation, ndt, and repair of concrete structures presented by. The best practice guidelines document is intended to be a technical resource that provides the most complete information for structural fireresistant design at present.
Concrete is one of the best fireresistant products found in the construction of buildings and flatwork. Steps for concrete damage repair in reinforced concrete structures 1. Much of the concrete is charred, but otherwise appears to be in sound condition. The following summary discusses potential causes of concrete deterioration and the factors that influence them. Exposure of concrete to intense heat will cause deterioration of its strength and durability. Those extraordinary positive results document, that reinforced concrete structures with additional fibre reinforced concrete can achieve fire resistance classes of r60 without additional provisions. Repair of firedamaged reinforced concrete members with axial load. Evaluating fire damage to concrete structures concrete. Concrete can deteriorate for a variety of reasons, and concrete damage is often the result of a combination of factors. Damaged reinforced concrete structures in fire core. In this study, experimental results highlighting the effectiveness of using unidirectional glass and carbon frp for repairing heat damaged circular reinforced concrete columns are presented. Maximum chloride ion content of concrete aci 318 maximum type of member cl prestressed concrete 0.
The method involves measurements on test cores from the damaged structure. This article summarizes an engineering evaluation of the extent of fire damage to a concrete structure under construction. Data was obtained by exposing two types of specimens to different levels of. Deicing salts are a major cause of corrosion of reinforcing steel in concrete. Damaged and lose concrete is removed around steel bars. A survey of firedamaged reinforced concrete structures in wardamaged zones of beirut central district bcd was conducted after the civil war was over in 1990. This multidisciplinary research focuses on the effect of fire on structures due to the boko haram insurgency in maiduguri, northern nigeria. A number of sensors were used to monitor the kinematic and thermal fields during the test. In this case, the effects of heat during an ongoing incident could have caused serious injuries or death to responders or civilians who had not maintained adequate distance from the area of collapse. The shoring has to be checked before concrete removal begins.
Assessment of firedamaged structures most firedamaged structures can be successfully repaired, this being the more costeffective solution than demolition and reconstruction. Of more importance, though, is the depth and extent of the fire damage. Moreover, models for predicting the residual strength of fire. The effects that fire has on the compressive strength of concrete are outlined in astm c 856. Performance of firedamaged prestressed concrete bridges. Steps for concrete damage repair in reinforced concrete.
Outline conditional assessment of fire damaged structures. A fullscale reinforcedconcrete rc threedimensional 3d frame under vertical sustained loads has been subjected to biaxial lateral loads representing earthquake actions followed by a pool fire in a single compartment. The emphasis of this report is on the methods of assessment and the extent of the required repairs. Assessment and repair of firedamaged concrete structures. Of the materials considered, ultrahighperformance fiberreinforced concrete uhpfrc exhibits huge potential for repairing firedamaged rc structures but lack of information available. Concrete is widely used for the construction of infrastructures such as buildings, bridges, cooling towers, chimneys, industrial and other numerical structures. Deng and wang 48 evaluated the performance of the bridge columns after 2hour fire exposure.
A modified layeredsection method for responses of fire. Its behaviour as fire resisting element caused most of fire damaged structure being reused after the fire, provided structural assessment has been carried out. However, the visual appearance of concrete after a fire can be quite shocking with extensive blackening often accompanied by spalling and cracking. Fire damage assessment of reinforced concrete structures. Flexural strength and serviceability of the bridge were measured by inputting fire damaged data into a parametric study spreadsheet consisting of a typical 3span continuous prestressed concrete bridge. With concrete and masonry construction, repair options insitu restoration or removal and redlacement versus demolition and addition, because of the superior inherent fire resis tance of concrete and. Hence, further studies must be performed to assess the potential of uhpfrc in rehabilitating firedamaged rc structures.
Review of repair materials for firedamaged reinforced concrete structures. However, intensive heat not only affects concrete, it can weaken it to the point where the only solution is replacement. Testing concrete in structures, a guide to equipment for testing concrete in structures, chl 3ciria technical report 143, 1992 the reinstatement of fire damaged steel and iron framed structures, corus british steel, 1986 assessment and repair of firedamaged concrete structures, concrete society technical report 33 1990technical report 33. Seldom does even a major fire cause total destruction, however, most firedamaged concrete is repairable. Pdf evaluation and repair of fire damaged reinforced. What effect do elevated temperatures have on concrete. Most firedamaged structures can be successfully repaired, this being the more costeffective solution than demolition and reconstruction.
Repair of fire damaged structures the concrete society. Corrosion of reinforcing steel is the most common cause of concrete deterioration. Visual assessment of fire damaged concrete fire safety. Myths of reinforced concrete fire damage concrete burns concrete consists of noncombustible mixture constituents and therefore as a hardened product, concrete wont burn. This work begins by detailing the major inconsistancies between designing reinforced concrete structures for extreme mechanical loads and designing for fire. Over the years many methods and devices have been developed to help the engineer assess the. This work begins by detailing the major inconsistancies between designing reinforced concrete structures for extreme mechanical loads and. Effects of fire on concrete structures not just another fire. Concrete, even though it may be the most fireresistant of all the major building materials, can be damaged by fire. Does the concrete need to be replaced after a fire. Were involved in the repair of a firedamaged building. The reinforced concrete was exposed to astm e119 standard fire for 45 or 90 min. Assessing concrete strength in firedamaged structures.
If the lateral support of the foundation was altered by the events related to the fire, it is possible the foundation wall could be subjected to. Once a reinforced concrete rc structure is damaged by. Effects of fire on the strength of reinforced concrete. The fire occurred in a portion of the reinforced concrete structure and visibly damaged a load bearing exterior foundation wall. In this research, a laboratory assessment of firedamaged reinforced concrete rc slabs was carried out by using. In this article, results of the investigation of one prominent structure in bcd, the opera theater, are presented. To determine whether the firedamaged structure can be repaired, an assessment of structural integrity must be conducted. Fire damage assessment of reinforced concrete structures using fuzzy theory haechang cho 1, deuck hang lee 1. Concrete has good fire resistance and concrete structures generally perform well. Limpaninlachat 2012 investigated the bond behavior between firedamaged reinforced concrete and cfrp plates.
After a severe fire, concrete structures are generally capable of being repaired rather than demolished. Fire damage, evaluation, ndt, and repair of rc structures introduction fire damage evaluation methods. The design approaches used to assess the strength of repaired elements, illustrated by example, are in accordance with the relevant eurocodes. Structure magazine engineering evaluation of fire damage. Firedamaged concrete concrete construction magazine. Review repair of firedamaged reinforced concrete members. Detailed information of the effects of high temperatures on.
The purpose of this paper is to outline some of the proposed changes to the concrete society technical report 15 which is the most comprehensive uk document dealing with assessment and repair of firedamaged concrete structures. A modified layeredsection method was developed in this article, which was not only able to determine the complete static resistancedeflection curves of firedamaged reinforced concrete beams but also able to predict the responses of reinforced concrete beams subjected to blast after fire exposure. Recent studies utilize fibre reinforced polymer frp in repairing firedamaged concrete. Once a reinforced concrete rc structure is damaged by fire, the fire damage assessment should proceed to take appropriate postfire actions, including the decisionmaking of whether it can be repaired for reuse or not. Review of repair materials for firedamaged reinforced. Ultra high performance fiber reinforced concrete uhpfrc mostly developed using fine size. Study has been aimed to establish a structured solution for rehabilitation and retrofitting of fire damaged concrete buildings. However, to date very limited research has been conducted investigating the repair of fire damaged reinforced concrete structures with frp. In general, reinforced concrete structure performed well under fire. The publication is being updated to take into account changes of practice and methods of assessment since 1978. A new innovative method, optical deformation measurement, provides a visual assessment of fire damaged concrete. The results provided by this technique usually present a high scatter and are only representative of a 3 cm layer of concrete 5. Reference concrete society 1990 provides detailed guidance on assessment of fire damaged concrete structures and design for repair. An innovative approach assuring the successful repair of.
Best practice guidelines for structural fire resistance. Reinforced concrete structures behavior solutionsforthebuiltworld page8 reinforced concrete structures visual distress. Examples of the fire behaviour of concrete structures during. As noted in the publication concrete and fire produced by the concrete centre, concrete does not burn it cannot be set on fire like other materials in a building and it does not emit any toxic fumes when affected by fire. Finally, the section enlargement method was adopted to repair the fire damage bridge columns. Uhpfrc as repair material for firedamaged reinforced. Inspection and rehabilitation of fire damaged reinforced concrete structures 2 correlated with the compressive strength of concrete using a conversion chart provided with the equipment. There are a number of onsite and laboratorybased techniques available to aid in the diagnosis of reinforced concrete condition. Uhpfrc to be utilized as repair material to fire damaged concrete structure based on previous. Vibration of reinforcement should be avoided to prevent damage to its bond with concrete around repair zone. Guidance on assessment is given in concrete society technical report 68, assessment, design and repair of firedamaged concrete structures. Introduction the ultimate strength of rc columns degrades in. When a building is damaged by fire, an inspection to assess the structural damage should be conducted as soon as possible after the fire.