American Society of Civil Engineers


Strength of Glued-In Bolts after Full-Scale Loading


by M. Uhre Pedersen, Ph.D., (Student, Dept. of Struct. Engrg. and Mat., Tech. Univ. of Denmark, DK-2800 Lyngby, Denmark. E-mail: mupbkm.dtu.dk), C. O. Clorius, Ph.D., (Student, Dept. of Struct. Engrg. and Mat., Tech. Univ. of Denmark, DK-2800 Lyngby, Denmark), L. Damkilde, (Assoc. Prof., Dept. of Struct. Engrg. and Mat., Tech. Univ. of Denmark, DK-2800 Lyngby, Denmark), and P. Hoffmeyer, (Assoc. Prof., Dept. of Struct. Engrg. and Mat., Tech. Univ. of Denmark, DK-2800 Lyngby, Denmark)

Journal of Performance of Constructed Facilities, Vol. 13, No. 3, August 1999, pp. 107-113, (doi:  http://dx.doi.org/10.1061/(ASCE)0887-3828(1999)13:3(107))

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Document type: Journal Paper
Abstract: In 1993 after 9 years of use, one of the wooden blades of a windmill was struck by lighting. After demounting, the damaged blade was handed over to the Technical University of Denmark, Lyngby, for the investigation of potential fatigue damage. This paper presents an experimental determination of the residual strength of the glued-in bolts that served as the blade to rotor hub connection in the windmill. The load history of the bolts, the test method, the observed fracture modes, and the force displacement curves are presented along with the recorded residual strength of the bolts. The bolts with a length of 500 mm had a special hollow tapering giving them a higher load-bearing capacity than solid bolts of equal dimensions. An FEM analysis confirms the higher load-bearing capacity. The mean residual strength was found to be 362 kN with a standard deviation of 37 kN, which is 95% of the predicted strength based on short-term tests on similar bolts. At fracture, a displacement between 0.4 and 1.0 mm was observed. In the majority of failures, the bolts were pulled out like a cork from a bottle.


ASCE Subject Headings:
Adhesives
Bolts
Fatigue
Laminated materials
Load bearing capacity
Residual strength