Strengthened of Wooden Trusses Structure and Retrofitting Methods to Increase Load Capacity

Assessing after the strong earthquake, several wooden truss structures were damaged. The damage varies from dislocation of the truss mounts with their supports, displacement between the curtain rods and truss frames as well as damage to the truss joints themselves. This research will study the types of damage, causes and methods of strengthening and repairing element of roof truss and frame that were damaged after a strong earthquake based on the level of damage, method and materials suitable for implementation. Data on the damage to the truss structure described were obtained from field assessments as well as secondary data from earthquake events from various regions in Indonesia and other parts of the world and segmental testing of truss. Failed in tension, compression, shear and support were found due to insufficiency of connecting devices and incomplete configuration of truss elements. The age factor and the wood material preservation system also cause the level of damage to the frames of these horses to be higher. Conventional strengthening methods using wood, iron, stainless steel, steel wire/cable, and the addition of connecting devices such as pegs, nail, screw, bolts, steel plates, tooth plate connects, and steel anchors are sufficient to increase the strength and rigidity of the wooden truss frame structure system. but not significantly increase the ductility. Alternative materials based on resins and polyurethane / polyether adhesives and healed wood have the potential to used. The results showed that the use of this type of material can increase the ductility and strength of 20-40% over conventional reinforcement systems such as nails and other connecting devices. Retrofitting L joint with strip plate, C70.35.0.45 stainless steel and L35.35.3 can increase maximum load capacity with ratio 1.25; 1.64 and 1.87 respectively.