Advanced Materials Research Vols. 133-134

Abstract: The purpose of this research is to determine the mechanical properties of damaged historic masonry walls retrofitted with Glass Fiber Reinforced Polymer (GFRP) under axial load through experimental method. Five masonry wall specimens were tested under axial load acted at the top surface. One wall specimen was served as reference without retrofitting. Two walls were retrofitted with GFRP before damage. Other two walls were repaired using epoxy injection and GFRP sheets after predefined damage. The results show that the bearing capacity of historic masonry walls was completely restored and even exceeded the original capacity.

Abstract: Retrofitting and moving protection for historical buildings have vital historical and cultural value for they concern both the development of human society material civilization and the continuation of human cultural heritage. Jinan City is ranked among the second group historic and cultural cities of China, where has many valuable historical buildings. The urban construction advances by leaps and bounds in Jinan City since the nineties, which brings tremendous challenge for the protection of historical buildings. The state of the art of protection and retrofitting for the historical buildings in Jinan City is summarized. Three protection schemes, namely in situ retrofitting and minimum distance moving protection as well as long distance moving protection, are adopted in Jinan City. Six finished protective projects are discussed from a structure viewpoint. Retrofitting and monolithic moving techniques are presented for different historical buildings according to the style and features as well as requirements, and also the pivotal techniques for improving aseismatic performance are suggested. Some retrofitting details as to members are also introduced. This will be helpful for the protection of historical buildings.

Abstract: For load-bearing capacity reducing of the walls of multi-storey masonry structure caused by the lower mortar strength and quality defects, the mortar replacement method was used to reinforce the perforated brick load-bearing walls. The strength of mortar used for replacing, the depth of replacement, construction methods and quality control have been studied. The reliability of this method is verified by testing in situ including axial compression test and double brick double-shear test for reinforced brick masonry. This method could be also used in reinforcement for the historical masonry buildings.

Abstract: vThe 4R principle refers to reduce, reuse, recycle and regeneration, which should be implemented in the process of concrete treatment. In terms of the special micro-structural properties and self-repairing capacity, concrete is one kind of regenerative construction materials. Through proper handlings, self-repairing (crack close-up) of concrete cracks is possible in the concrete hydration damaged region. Due to the effect of heterogeneous nucleation and subsequent crystal growth of calcium hydroxide, a better bonding strength forms interlocking the new and old concrete interfaces. A proposal on the relationship between the self-repairing, regeneration function of concrete and the rehabilitation of historic buildings is suggested, this is based on the formed process of the bonding strength of the interfaces and the function on concrete repairing. Besides the constitution and features of the microstructure of concrete, the relationship between the micro-structure and the macro-mechanical property is also investigated in this paper

Abstract: Masonry heritage building built during early part of 19th century have characteristic colonial architecture using masonry walls and jack arch roofing supported on steel beams. They are highly vulnerable to failure during earthquakes. This paper describes a methodology to quantify their vulnerability and then based on this a scheme of structural retrofitting is suggested. The aim of this presentation, through 4 case studies of buildings located in Delhi, India, is to exemplify various aspects of analysis, design and execution methodology of the retrofitting scheme for such important heritage structures. The assessment of vulnerability is based on its location, codes of practice with respect to materials and loading. The main challenge in choosing the appropriate retrofitting scheme lies in retaining the architecture and aesthetics. Also the retrofitting has to be completed in the least possible time causing minimum disturbance to the occupants. This has been achieved through a combination of Ferro-cement bands and FRP sheets. The execution of retrofitting was considered to make use of available local materials and expertise. The building is analysed in detail and the areas where stress concentration takes place is further strengthened.

Abstract: The preservation and conservation of deteriorated historical structures is always a difficult but challenging task. Theoretically, all significant historic structures should be conserved and saved from being removed or discarded. Practically, this ideal may not always be achievable for all decayed components of the historic structures. Sometimes their conditions are too bad to be reasonably repaired to a safe state. On the other hand, replacement is not the only resort for all the damaged relics. There are situations that these relics should better be preserved, though more resources will have to be invested and greater challenge might be encountered in the course of work. This paper attempts to illustrate the deliberation with a case study - the preservation of wooden structures of Chik Kwai Study Hall in Hong Kong, and addresses the considerations in making decision between repair and replacement. Scientific or structural analysis has played a key role in directing our way to the final decision. Methodology used for guiding the whole conservation process will also be discussed.

Abstract: This paper is an overview of structural interventions which should be made to the Baroque Oppersdorf Palace during its renovation. All main technical problems were analyzed and proper constructional solutions were presented. Several characteristic types of destruction were detected, caused by natural deterioration and also by mechanical influences (war destruction, lack of conservation etc.). The main building structure has survived from the Baroque period, except for the wooden roof. Some of the cellar vaults and some of them over the first floor were also not destroyed. However, some main reconstruction work was done, probably in the last few years of the 19th century. For example, a break with a new staircase and some masonry vaults over the cellar were changed to ones of Klein type on steel beams. The main aim of the reconstruction was to strengthen the historical structure of the building and adapt it to the modern architecture and to reorganize the buildings inner space, but keeping the external proportions, architectural details and ornaments unchanged.

Abstract: Some aspects of the revitalization of the 14th century historical building are presented in the paper. The building was originally used as a poorhouse and a hospital for children. The original Gothic masonry building on the site was a two-storey building with a cellar, situated in a corner of two streets. In the middle of the 19th century the building was converted into a school and then the first large-scale demolition of the hospital’s Gothic walls took place. After the 2nd World War a school was also situated in the building, where it existed until the late nineties. The aim of the renovation process was to convert it into an exclusive office block. The design works were preceded by historical research and on-site investigations. Complex conversion of the object consisted in the reconstruction of the old building structure, creating the inner courtyard and covering it with a glass roof. In the existing part of the basement one of the longest single-nave vaults in Poland and the exquisite roof truss system with a lying bidding-rafter post deserved special attention during the renovation.

Abstract: In the present paper, a project for integrated investigation is described, using noninvasive methods, specially designed for dealing with the highly diversified historic heritage of Piedmont (Italy). The stability of the decorated surfaces will be investigated by innovative Acoustic Emission (AE) and ultrasonic methods already experimentally tested in the field of artistic and monumental cultural heritage in Italy. The ultrasonic investigation techniques allow assessing separations, defects and damage phenomena that can regard the decorated surfaces and the masonry supports. Innovative acoustic methods will allow distinguishing a well-preserved artwork in comparison to a damaged one providing a quantitative criterion for the definition of intervention priority.

Abstract: This paper discusses the different techniques that can be adopted for conservation and preservation of historical earthen structures constructed using adobe mud bricks in non-seismic regions. Initially, it reports the different damage patterns and modes of failure that are usually exhibited by these structures due to aging process and poor environmental conditions as recorded from field visits. Then, it explains using structural fundamentals and soil mechanics principles the causes for these defects. Finally, it suggests various measures that can be taken to restore and preserve these endangered structures.