Masonry construction has a very long tradition and is the most commonly used type of construction. Because of its simple and economical production it will continue to be of major importance also in the future. In particular, its properties in terms of building physics ensure that it remains economically relevant. Nevertheless, low tensile, flexible, and shear load bearing capacity can be a great disadvantage of masonry. In countries with high earthquake risk and social and economic problems, construction materials of poor quality are being used quite often. Especially in rural areas, use is made of bricks and mortar of low tensile strength classes that are hardly used any longer in Europe. The masonry panels used as braces in one and two storey constructions are hardly able to withstand earthquake loads and display a low shear capacity. Since other types of construction are impossible to apply for economic and ecological reasons, these constructions should be strengthened retrospectively after they have been erected. One method used in recent years is the retrospective strengthening using fiber composites applied adhesively to the masonry surface. The most commonly used fibers are carbon fibers (CFRP) and glass fiber-reinforced synthetic materials (GFRP). These materials in combination with synthetic resin systems are already common for example in Switzerland and the USA, but because of their high cost and low availability are hardly used in earthquake regions with economic problems, such as in the Near and Middle East or Latin America. In addition, modern reinforcement materials such as CFRP and GFRP are too rigid for ‘weak’ masonry and can lead to compatibility problems. For this reason, clearly less expensive materials that are adapted to properties of the masonry described are necessary. Natural fibers in combination with filler compound of an epoxy resin base or epoxy resin enriched fine filler on a cement base can, for both cost and compatibility reasons, provide a very attractive alternative. Test results on masonry strengthened with such natural fiber textiles and theoretical investigations as well as a pilot application to the World Cultural Heritage site Arg é Bam (Iran) will be presented. The research whose results are reported in this contribution was conducted at the Institute for Materials Engineering (Professor M. Schlimmer) of the Faculty of Mechanical Engineering in cooperation with the Institute of Structural Engineering (Professor E. Fehling) of the Faculty of Civil Engineering at the University of Kassel. The pilot project at the world heritage site was implemented by the first author in a period of self employment with the support of UNESCO and Sika Schweiz AG. Copyright © 2011 IAHS.
Indoor environment especially concerning to interior architecture affect us not only by their mass, surfaces, color and shapes. Indoor surfaces mostly emit the compounds which have great impact on human beings. Growing attention is being paid to indoor air quality as one of the main health and well-being factors, also in Slovakia. The Building and Environmental Engineering Institute is concerned to indoor sciences research work within indoor environmental engineering orientation of the structural architecture. Today, the buildings are divided into: very low-polluting, low polluting and not low polluting. The classification of buildings is affected by the approach in selecting low emitting materials and restricting activities that emit pollutants into the environment of buildings. Therefore, the interior material surfaces selection is important from volatile organic compounds (VOCs) occurrence point of view. The main subject of the last period interest is and the materials emissions. Several office interior surfaces emissions are compared in this study. Comparing performed by chemical analysis and sensory tests using the test chamber. Methodology of material comparison is based on the volume of total volatile organic compounds (TVOCs) in the air. It has become evident that building materials are the major source of indoor volatile organic compounds. The indoor air acceptability and indoor air quality concerning to several types of interior materials are presented in this case study. The impact of individual materials and their interaction effects to the indoor air quality will be discussed within the paper. Copyright © 2011 IAHS.
In the thought of Peter Rice when the architectural design challenges the laws of nature the structure becomes architecture. A research, developed at the Department of Architecture and Urban Planning of Catania, proposes a reinforced masonry that is built with blocks of natural stone instead of artificial blocks. [8] This occurs because the local stone (basalt) has similar characteristics to artificial blocks used generally to build masonry. This research has interested different aspects related to the building procedure (construction, structural, thermal and environmental aspects). [3-4] Obtained results show good performances of reinforced masonry built with basalt. Law in seismic zone sets some limitations to the building of reinforced masonry for thickness, thinness and restraint conditions. Within this problematic a new phase of this research has been started with the objective to appraise characteristics of prestressed masonry built with basalt. This paper shows the contribution that pre-stressed masonry built with basalt offers in architectural design. Copyright © 2011 IAHS.
The recent introduction in Spain of the Building Technical Code (CTE) means that CE labelling is now mandatory on construction products that will be permanently incorporated in buildings. One of the requirements with which manufacturers of precast slabs must comply in order to obtain the CE mark of conformity on their products is the satisfactory completion of tests that guarantee the resistance/strength qualities that are shown on the certificate of conformity. Load-bearing beams and reinforced concrete precast slabs imply greater quality control at the manufacturing plant, shorter construction periods and improved safety at the construction site. They may also be used as resistant plank moulds during execution. The purpose of this study is to determine the span in construction (the distance between false-work) for the bearing beams and RC slabs during the construction phase. It is intended to optimize the number of false-work structures to be calculated to withstand their own weight, the weight of the poured concrete and an additional under construction load of 1KN/m2. The criteria used to calculate the span in construction were the ultimate bending strength, the ultimate shear strength and the flexural rigidity. The tests are in compliance with Standard UNE-EN 13747:2006 whereby the distance between props or temporary bearings of the span in construction is specified. The testing method used was four-point bending. The test consisted of supporting the bearing beam or slab on two end supports and applying two equidistant equal loads to the span. The results for extreme bending strength are very similar and a fraction higher than the theoretical results that might have been expected. The fineness ratio corresponds to the curve of the upper bars observed in the flexural load tests. The results of the extreme shear strength are about twice as high as the expected theoretical values; values which may be readjusted with a lower slenderness ratio. Copyright © 2011 AHS.
In old city centers, the majority of these buildings were mainly designed as loadbearing masonry structures (stone or ceramic bricks), with timber structured floors and roofs. As consequence of aging, loading (sometimes accidental), alteration of use, moisture content, lack of maintenance and repairing actions, amongst others, these buildings have slowly decayed, particularly timber elements of floor structures and roofing systems more susceptible to the degradation of the load bearing capacity and sensible to excessive moisture problems at the connection areas with masonry walls, aggravating stress levels of the timber resisting elements, even in cases when subjected to seismic action. This paper, intends to deepen existing studies, by proposing strategy definition for retrofitting and strengthening of timber floors, taking into account that wood is considered a noble material, with excellent structural properties, ecological and sustainable. So, taking into consideration specific limitations of old buildings and preventing the loss of authenticity of the original materials, it is suggested the use of similar materiais, assuring the safety and durability of structures, as well as the improvement of the serviceability conditions of buildings. To consider the presented solutions in terms of execution, it is necessary to resource to strategy definition tools to complement the inspection tasks and defect identification, as well as compatibility of performance levels (thermal, acoustic and structural), or definition of eventual non destructive ‘in situ’ testing if needed. Copyright © 2011 IAHS.
The final disposal route of post-consumer recycled glass (RG) is a common issue for many municipalities worldwide. Approximately 1 million tons of glassware is produced per year in Brazil, only 47% of which are currently recycled. The idea of incorporating RG as aggregate for concrete emerged in the 60’s motivated by some of the advantages of glass, i.e. low water absorption, high abrasion and durability aesthetic potential among others. However, the initial researches have shown that concretes containing RG exhibited marked strength regression and excessive expansion due to alkali-aggregate reaction (ASR), which limited further research The topic emerged again in the 90’s, imposed by the sustainability issues. Moreover new studies aimed to determine the conditions at which ASR does not occur, as well as the influence of RG on the physical properties of concrete. Despite some literature on the use of RG into concrete, its application for making concrete roof tiles is still not documented. The incorporation of RG into those products, if feasible, may create a sustainable material for construction by reducing the land-filling of RG in municipalities near the concrete tile plants. This paper investigates the use RG as replacement of 7.5% and 15% silica aggregate in concrete roof tiles. Three grading of RG were studied, i.e. particles retained between 4.76 – 1.68 mm, 1.68 – 0.84 mm and 0 84 – 0.30 mm sieves. Metakaolin (MK) has been chosen to replace 7.5% and 15% wt. cement and potentially suppress ASR. The physical properties assessed were dry bulk density, compressive strength and modulus of elasticity; the engineering properties determined were apparent porosity and oxygen permeability. Results showed that the use of 7.5% RG in combination with 7.5% MK provided equivalent performance to reference semi-dry pre-cast concrete and, therefore, permit a new route of disposal for the RG. Copyright © 2011 IAHS.
