General Perspectives on Seismic Retrofitting of Historical Masonry Structures

This chapter focuses on retrofitting of historical masonry structures from the point of seismic resistance based on failure analysis. In historical structures, restoration applications have become necessary because their life cycle of structural and nonstructural members is completed due to natural result of material structure, environmental conditions, and/or user errors. One of the most important intervention decisions in restoration stages carried out in historical buildings is known as retrofitted of the structure. The choice techniques of retrofitting of the structural members are becoming a very important issue in the scope of restoration of historical masonry structures belonging to the cultural heritage. Additionally, it should be decided to optimally preserve such buildings’ original forms and to make interventions to increase the building’s service life; in this regard, it is important to preserve the structures’ historical identity and constructional value. Therefore, retrofitting applications have become essential to prevent the damage level and to have adequate level of structural strength in order to resist dynamic effects such as earthquakes. In this chapter, it is aimed to determine the main principles by using conventional and modern techniques within the scope of laboratory tests and numerical approaches in recovering the historical structures

Structural damage caused to RC buildings by tunnelling work

Nagli pomaci u tlu mogu dovesti do oštećenja armiranobetonskih građevina. Takvi pomaci mogu između ostalog biti uzrokovani gradnjom tunela, pa se utjecaj takve gradnje treba uzeti u obzir u postupku projektiranja građevina. U ovom se radu na primjeru postojeće bolničke zgrade analiziraju konstrukcijska oštećenja armiranobetonske građevine uslijed naglih pomaka tla. Kako bi se dobili što točniji podaci za potrebe analiza, primijenjen je multidisciplinarni pristup radi povezivanja raznih inženjerskih disciplina koje su sudjelovale u ovom istraživanju.Structural damages to RC (Reinforced concrete) buildings occasionally occur as a consequence of sudden ground movements. One of these is effect of tunnel excavation on the structures and the design process should be carried out by taking the effect into account. In this study, the structural damages caused by the impact of sudden movement emanating at the ground were investigated for a selected hospital building. Within the scope of this study, it was aimed to obtain the most accurate data by combining different engineering disciplines through a comprehensive approach

The conservation and repair of historical masonry ruins based on laboratory analyses

Historical masonry structures that remained under the ground due to settlement have to be revealed and preserved because of their historical values. The study focuses on assessment of wall ruin from early Byzantine period and the arched vault ruin from Ottoman period. In this study, the properties and problems of the materials as mortars and woods were analyzed, which were gathered from the ruin structure wall, vault, brick pipe and bonding wood. The study consists of the on-site examination, laboratory analyses and application proposals about the wall ruin from early Byzantine era and arched vault ruin from Ottoman era which were unearthed during the re-construction of education building. In the first stage of study, representative samples taken from different locations of the masonry ruin were exposed to chemical- and mineralogical-analyses, and the content of samples were determined. In the second stage, the data of analysis were assessed, then the conservation and repair proposals were submitted for implementing on the masonry ruin. By proposed materials for the conservation, it will not be occurred mechanical stresses due to the original and new repair mortar- and wood-materials have the similar physical and mechanical properties. Thus, this will lead to long and healthy life to the original materials of the ruin structure. (C) 2016 Elsevier Ltd. All rights reserved

Characterization of ground slag and borax waste and their effects on the compressive strength of briquettes

The usage of briquettes is preferred in the construction industry for many years. The quality of briquettes is directly related with characteristic features of raw materials and their compositions, production procedure, firing method, temperature and duration. There are waste materials such as borax waste having been used for briquette production, however it is not available to combined of both borax and ground slag used in briquette production. In the study, both borax and ground slag were used together as an additive in order to observe effects on the material characteristics of briquette samples. In this scope, compressive strength and bulk density of the samples produced using borax and ground slag were defined. Moreover, SEM-EDS, XRD and DTA/TG analyses of the materials were carried out and discussed. The overall results have concluded that not only higher compressive strength results were obtained using these wastes, but also the usage of waste up to 22% ratio was provided for this study. Consequently, it is determined to be possible using borax waste and ground slag in briquette production. (C) 2016 Elsevier Ltd. All rights reserved

Seismic retrofitting of the historical masonry structures using numerical approach

In historical buildings, because of the deterioration on structural members including slab and walls that complete their life cycle in time, due to environmental conditions; restoration applications have become necessary to increase the material durability level and to have adequate level of structural strength in order to resist dynamic effects such as earthquakes. This paper focuses on assessment of historical masonry structures from the point of seismic resistance. The entire process is illustrated using case study from a historical masonry structure. In this study conducted in this respect, a historical building is restored within the scope of laboratory studies and numerical analyses. The first stage of the study includes plaster analyses and mechanical tests conducted on the samples taken from the said building. In the second stage, i.e. numerical analysis, the building's existing 3D computer model was prepared and materials, members that are inadequate in terms of strength were determined. The third stage includes restoration applications by using laboratory and numerical analysis results. Within the scope of restoration applications, structural cracks on the walls were repaired using the injection method; volta slab (brick floor arches), exterior facade walls, interior walls and door/window gaps using different techniques were strengthened. In this study, it was aimed to increase material durability and structural strength by using conventional and modern techniques within the scope of laboratory tests and numerical approaches in recovering the historical buildings. (C) 2016 Elsevier Ltd. All rights reserved

Restoration of the historical masonry structures based on laboratory experiments

In historical structures, restoration applications have become necessary because their life cycle of structural and non-structural members is completed due to natural result of material structure, environmental conditions and user errors. In this study conducted in this respect, conventional and modern techniques which is conserve the historical building's identity were adopted by referring to opinions of expert consultants and academicians within architecture and civil engineering fields. The first stage of the study contains; i. Specify of material characteristics, ii. Determination of mixture ratios using physical and chemical tests conducted on samples taken from the building, iii. Preparation of original material mixtures using the obtained data. In the second stage, architectural implementations were determined based on lab test results. Within the scope of architectural implementations, featureless additions that do not comply with the original materials of the building, floor/ceiling tiling and wall plasters were removed; masonry members on facades and floors were completed, repaired and cleaned; doors and windows were renovated; stairs and safety rails were returned to their original condition. Finally, a survey was carried out to determine whether the restoration was effective and to evaluate the building's relationship with urban environment, its aura and universal originality as well as its originality of material, form and function. It is concluded that the developed historical building restoration process is suitable as a practical tool in the historical building restoration studies for the prediction of accurate restoration applications. (C) 2016 Elsevier Ltd. All rights reserved

Constraint Factor in Optimization of Truss Structures via Flower Pollination Algorithm

The aim of the paper is to investigate the optimum design of truss structures by considering different stress and displacement constraints. For that reason, the flower pollination algorithm based methodology was applied for sizing optimization of space truss structures. Flower pollination algorithm is a metaheuristic algorithm inspired by the pollination process of flowering plants. By the imitation of cross-pollination and self-pollination processes, the randomly generation of sizes of truss members are done in two ways and these two types of optimization are controlled with a switch probability. In the study, a 72 bar space truss structure was optimized by using five different cases of the constraint limits. According to the results, a linear relationship between the optimum structure weight and constraint limits was observed