EXPERIMENTAL STUDY ON PRESTRESSED-HIGH-STRENGTH-LIGHT-WEIGHT -CONCRETE CONTINUOUS RIGID FRAME BRIDGE

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1 24 I Vol.24 Sup. I 27 6 June 27 ENGINEERING MECHANICS (27)Sup.I * ( 184) CL4 (HSLWC) 14 1/4 3 CL TU375 A EXPERIMENTAL STUDY ON PRESTRESSED-HIGH-STRENGTH-LIGHT-WEIGHT -CONCRETE CONTINUOUS RIGID FRAME BRIDGE HUANG Sheng-nan, LIU Ying-kui, * YE Lie-ping, SUN Hai-lin, FENG Peng, LU Xin-zheng (Department of Civil Engineering, Tsinghua University, Beijing 184, China) Abstract: High-strength-light-weight concrete (HSLWC) (with a cube strength higher than CL4) has a bright future in the application of large-span bridges due to its obvious advantages. It reduces the self-weight of the bridge, so that the internal stress can be smaller, the span can be larger and the number of piers can be reduced. An experimental research on a 3-span prestressed continuous rigid frame model bridge with a superstructure made of CL5 HSLWC is presented in this paper. The prototype of the bridge model is located in the 14th section of the highway connecting Anning and Chuxiong in Yunnan province. The model bridge was designed by the scale of 1/4 and was tested under 1 different load cases. The test results showed that the prestressed HSLWC continuous rigid frame model bridge had good mechanical performance. Under a traffic load which was 1. to 1.5 times of its design load, all indices of the bridge model satisfied the requirement of design standard. And under 2 times of design load, parts of indices were beyond the standard requirement but the bridge still showed good ductility. And under very large overload situation, the bridge was damaged seriously but it still could maintain the load capacity and did not collapse. Key words: rigid frame bridge; model experiment; high-strength-light-weight concrete; prestress; residual deformation ( ) (1982) ( huangcn3@mails.tsinghua.edu.cn) (1976)( lyk3@mails.tsinghua.edu.cn) * (196) FRP ( ylp@mail. tsinghua.edu.cn) (1978)( shl97@mails.tsinghua.edu.cn) (1977) FRP FRP ( fengpeng@mail.tsinghua.edu.cn) (1978) ( luxinzheng@263.net).

2 135 (HSLWC) () CL4 16kg/m 3 ~195kg/m 3 25%~3% [1~5] LWC 8 [6] HSLWC [7] m~21.4m [8] HSLWC(CL 4) HSLWC HSLWC 14 1/ [9] JTJ [1] 1/4 f y 182MPa ( 2(d)) [11] 3(a) 25µε 3(b)~ 3(d) 1 17kN 3kN/m 1 Table 1 Material parameters of the model bride f y / MPa f / MPa / MPa Ф1 Ф12 7Φ kN( ) (1) a b c kN (2) a b c 2-2 5kN (3) d 4 ( 37.5kN) ( 28.3mm 1/3L)( 6mm 1/135L 18mm 1/75L) 2 4 6

3 136 (a) (b) 1 (c) 2 1 Fig.1 Original bridge and sections (a) (b) 1 (c) 2 (d) 2 Fig.2 Model bridge σ / f c ε / ε (a) MPa (b)

4 137 MPa MPa (c) 1mm (d) 12mm 3 Fig.3 Material testing results a (25kN) 3.66mm(37.5kN).5mm mm.15mm( 5(a)) ( 5b)( ) 2 b (25kN) 5.3mm (37.5kN).1mm 12.48mm 22kN.65mm( 5(a)) ( 5(b)) Fig.4 Load cases 2 Table 2 Load schemes () 1 A 37.5kN 2 B C 4 A 5 5kN 5 B 2 6 C kN kN mm( 1/3) 9 6mm( D 1/135) 1 18mm( 1/75) (a) ( 4) (b) ( 2) 5 1~ 3 - Fig.5 Load-deflection curves from load step 1 to load step

5 138 3 c (25kN) 3.98mm (37.5kN) 6.1mm ( 5(a)) 1 ( 5(b)) c 25kN.1mm 4.13mm 5kN.15mm 9.5mm( 6(a)).82mm ( 6(b)) (a) ( 4) (b) ( 2) 6 4~ 6 - Fig.6 Load-deflection curves from load step 4 to load step b 2kN - 4kN -.25mm 2.13mm 6 a 25kN.1mm 5.74mm 5kN.2mm 14.1mm( 1/61) 2.38mm () 2.3 7~ 11 d 7 1mm.3mm 8kN - ( 7(a)) 1kN 14kN ( 7(b)) kN

6 ( 9) (a) ( 4) Fig.8 Load-deflection curves at the middle span in load step 1, load step 3, load step 4 and load step (b) ( 2) 7 7~ 11 - Fig.7 Load-deflection curves from load step 7 to load step Fig.9 Load-deflection curves at the middle span in load step 2 and load step Table 3 Deflection, residual deformation and crack width 1P k / 25kN 1.5P k / 37.5kN 2P k / 5kN 3P k / 75kN 4P k / 1kN L/f w max / mm L/f w max / mm L/f w max / mm L/f L/f /mm P k P k 25kN L L 8.5m f w max 3 (1) (1 1.5 )

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