الفهرس 
CHAPTER (1): INTRODUCTIONOnly 14 pages are availabe for public view
 |  | from | 160 |  |  |
| | | from | 160 | | |
Abstract
Timber has a long history as a structural construction material. Timber is used in various construction applications, among which are shipbuilding, marine architecture and building constructions. In Egypt, the wood is used to form many architectural elements in historic buildings such as cantilevers, domes, ceilings, doors, floors and mashrabiyas. Timber elements were used in old constructions. When those elements age rehabilitation becomes a need. The main aim is to study the feasibility of repairing and strengthening of authentic timber cantilever beams used in valuable historic buildings and monuments. It assesses the effects of using different materials and techniques to repair and strengthening the structural wooden elements ”timber”. In this research, the effects of various suggested repairs on the structural performance of such elements, as well as on the impact on historic and architectural values of the elements were investigated. The research main variables are: adhesive material, repairing or strengthening material, repairing or strengthening technique, rather than the usual practice of replacing defected elements. The objective is to preserve those elements in their historical context, thus keeping the authenticity of the built fabric.
Forty-four cantilever wooden beams were tested under concentrated load at the free end point of the cantilever. The tests were conducted on historic timber and new wooden cantilever beam samples similar in shape, wood type and properties as the original ones. The beams were divided into four groups. The first group are beams with no repairs; to be considered as “reference”. The second was strengthened by using near surface mounted technique (by using three materials; steel plates, glass fiber reinforced polymer GFRP wrap and carbon fiber reinforced polymer CFRP laminates). The third was strengthened by using externally bonded reinforcing technique (by using three materials; GFRP wrap, CFRP laminates and Steel Plates)”. The forth was repaired by using epoxy injection.
Test results showed that repair and strengthening materials and techniques used in this study are all efficient from structural point of view. While using the externally bounded reinforcement system ”EBR” is more efficient for repair or strengthening of timber beams, consideration of visual impact of the repairs indicates that using the near surface mounted system ”NSM” is preferable. In the case of using ”EBR” or ”NSM”
methods, better values are obtained when using steel plates, followed by CFRP laminates then a GFRP wrap as repair or strengthening materials. Throughout the assessment of the result of the tests and the evaluation of the visual impacts of the selected repairs, the thesis concluded with a set of recommendations and suggestions.