A Study on the Structural Test and Mechanical Behavior of the GFRP I Beam Superstructure

Yeou-Fong Li1 and Yen-Chun Chen2

Keywords ： Fiber Reinforced Plastic, temporary bridge

Abstract :This study presents Fiber Reinforced Plastic (FRP) composite components used in temporary bridge for emergency relief. There are some advantages of FRP, including light weight, high strength, weather resistance and easy storage, making FRP suitable for temporary bridge. There are two types of FRP temporary bridge in this study. First type is pedestrian bridge. Second type is vehicular bridge. The pedestrian bridge is suspension bridge made by the cable, FRP deck, FRP bar and FRP frame. Use SAP2000 to establish the numerical model. Load several different types of loads to simulate the real load and check the safety factor. Finally, make the FRP suspension bridge. The vehicular bridge use FRP beam-deck system as superstructure. Use SAP2000 to establish the numerical model. Establish the numerical model of different spans. The type of the load is according to the design of bridge code. Then check the safety factor. Finally, make the best type of FRP vehicular bridge.

1Professor of the Department of Civil Engineering , NTUT, Taipei, Taiwan .

2 Master of the Department of Civil Engineering, NTUT, Taipei, Taiwan.

Non Transverse Beam

Transverse Beam

Non Deck N.A. W4X2-T4

Deck W4X2-PC

W4X2-PA N.A.

Double Plate(Supporting pad)

W4X2-P2 W4X2-TP2

ScrewDeckTransverse

Beam

BoltSupporting

PadScrew

Main Beam

The Small-Scale Model GFRP bridge superstructure (I girder-deck) system.

T4 is 3 Main Beam with 4 pair Transverse Beam fabricate by BoltPC is 3 Main Beam with Deck fabricate by EpoxyPA is 3 Main Beam with Deck fabricate by Epoxy and ScrewsP2 is 3 Main Beam with Deck and Supporting pad fabricate by Epoxy and ScrewsTP2 is 3 Main Beam with 4 pair Transverse Beam fabricate by Bolt and with Deck fabricate by Epoxy and Screws alsoL1 is 1 Main Beam in prototypeL1 C is 1 Main Beam in prototype connected at MidpointP2C1 is 3 Main Beam of P2 system connected at MidpointP2C1 is 3 Main Beam of P2 system connected at One-third point interlaced

Specimens Pmax (kN) K (kN/cm)

Failure mode

 

W4X2-L1 20.59 21.22 T 、 C  W4X2-T4 111.18 55.75 V 、 F  W4X2-PC 91.17 67.30 S 、 I  W4X2-PA 101.45 74.18 S  W4X2-TP2 118.06 79.57 F  W4X2-P2 141.94 71.9 C 、 F  

W4X2-L1C 19.03 19.89 T  W4X2-P2C1 107.62 67.35 B  W4X2-P2C2 105.74 61.21 B 、 W  

T: Lateral Torsional Buckling

C: Local crushing at loading area

V: Shear failure at loading area

I: Interface of the beam and deck fail.

S: Shear failure at the bearing

F: Weds cracking along fiber

direction

B: Bolts-hole tear

W: Webs cracked in connection area

Conclusions

Test Result

Midpoint One-third point

Connection W4X2-P2C1 W4X2-P2C2

The GFRP bridge superstructure (I girder-deck) system can be to avoid the prototype beam lateral torsional buckling.

Install deck, transverse beam and supporting pad appropriately, can avoid local crushing and shear failure, increase strength and stiffness.

When the strength is increased, the strength gradually passed to the webs of main beam, lead the failure mode changes to weds cracking along the fiber direction. This shows the interface strength of resin and fiber is not enough, the bolt hole will lead to a destruction occurred early.

The connection bolts at the midpoint will slip relatively suddenly than one-third point interlaced

In accordance with the span of the choice of Euler and Timoshenko beam theory formula can accurately predict the stiffness of the GFRP beam members.Local crushing at loading

areaShear failure at loading areaInterface of the beam and

deck fail

Shear failure at the bearing Weds cracking along the fiber direction

Bolts-hole tearWebs cracked in connection area