土木外文翻譯--高溫下鋼筋混凝土中鋼筋的性能

1、17外文原文：Research Letters in Materials Science Volume 2008 (2008), Article ID 814137, 4 pages doi:10.1155/2008/814137Research Letter Properties of Reinforced Concrete Steel Rebars Exposed to High Temperatures?lker Bekir To

2、pçu and Cenk Karakurt Department of Civil Engineering, Eski?ehir Osmangazi University, 26480 Eski?ehir, TurkeyReceived 12 February 2008; Accepted 31 March 2008Academic Editor: Rajiv S. MishraCopyright © 2008 ?

3、lker Bekir Topçu and Cenk Karakurt. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provide

4、d the original work is properly cited. AbstractThe deterioration of the mechanical properties of yield strength and modulus of elasticity is considered as the primary element affecting the performance of steel structur

5、es under fire. In this study, hot-rolled S220 and S420 reinforcement steel rebars were subjected to high temperatures to investigate the fire performance of these materials. It is aimed to determine the remaining mech

6、anical properties of steel rebars after elevated temperatures. Steels were subjected to 20, 100, 200, 300, 500, 800, and 9 5 0 ° C temperatures for 3 hours and tensile tests were carried out. Effect of temperature on mec

7、hanical behavior of S220 and S420 were determined. All mechanical properties were reduced due to the temperature increase of the steel rebars. It is seen that mechanical properties of S420 steel was influenced more th

8、an S220 steel at elevated temperatures. 1. IntroductionFire remains one of the serious potential risks to most buildings and structures. Since concrete is widely used in construction, research on fire resistance of 19w

9、ere subjected to 20, 100, 200, 300, 500, 800, and 950°C temperatures in a high furnace for 3 hours, respectively. At the end of the curing process, steels were cooled naturally to the room temperature. Subsequentl

10、y, tensile tests were applied to steel reinforcement rebars. According to EN 10002-1 tensile strength, yield strength and elongation of the steel rebars were determined for elevated temperatures [7]. The steel specime

11、ns tensile strength tests were performed with 60 tons of loading capacity universal tensile strength test machine. The loading speed of the test machine is adjusted according to TS 708 code [8].3. Test Results and Eva

12、luations3.1. Stress-Strain RelationsThe average values for stress-strain relationship for specimens that were exposed to various temperatures are given in Figures 1 and 2. The curves in Figures 1 and 2 were drawn with t

13、he average test results of 10 and 16 mm in diameter steel specimens. The test conditions were meant to simulate a building that had a fire so the changes in the mechanical properties of reinforcing steels used in struc

14、tures exposed to high temperature could be determined. As seen from Figure 1, temperatures below 500°C have no significant effect on mechanical properties of preheated and cooled S220 steel rebars. The yield stre

15、ngth and splitting tensile strengths of S220 steels were similar up to this temperature. However, the yield strength and splitting tensile strength of the S220 steel rebars are reducing with the increase of temperature

16、s over 800°C. A similar behavior can be seen from the test results of S420-ribbed steel rebars (Figure 2). All high temperature subjected steel specimens became more ductile temperatures above 800°C.Figure 1

17、: Stress-strain curve of S220 steel rebar.Figure 2: Stress-strain curve of S420-ribbed steel rebar. 3.2. Yield StrengthYield strength of both reinforcing steel rebars was affected with the elevated exposure temperatures

18、. It can be concluded from Figure 3 that there is no variation in yield strength of reinforcing steels with cover up to 300°C. Plain reinforcing steel rebars have experienced the strain hardening already for this