M.Ing. / This research project was initiated by a well-known international company (MAKRO SA), which had experienced floor joint problems occurring in their industrial floors. Floor joint problems i.e. joint damage and spalling of the joint area result, from a combination of construction workmanship and quality control problems, as well as from operational hard wheeled vehicle loading conditions. Damaging and spalling of joint edges are general problems occurring on warehouse floor slabs because of hard wheeled loads trafficking joints. In addition, joint filler detachment from the joint wall surface looks aesthetically poor and leaves the possibility of hygienic problems developing. In the case of MAKRO SA stores, the above problems are not acceptable and should be avoided at all costs. The objective of the report is to investigate solutions to solve the problem of joint damage in industrial floors due to problems occurring in practice, as described below. Floor joint edge problems are a result of three main reasons. First, subsoil quality. The quality of the subsoil is determined by the compaction effort and type of filler materials used, which in turn determine the amount of deflection that will be detected at joint edges. Subgrade quality determines whether deflection of the top concrete layer will occur. Poor compaction and filler material contributes to excessive deflection occurring due to inadequate support of the concrete floor slabs. Water penetration through the floor slab results in the fines of the subsoil being eroded or washed out, resulting in a less dense material, which will deflect under large vehicle and store racking loads. It is concluded that good quality subsoil conditions will result in less deflection and level irregularities of the top concrete floor slab, resulting in less joint damage and spalling. Secondly, the effect of floor and joint workmanship on damage and joint edge spalling. Level irregularities occur due to poor troweling or floating efforts at the joint area. Poor joint edge workmanship results from incorrect formwork removal from the joint wall resulting in a damaged joint edge and additional spalling of the joint to that occurring from wheel load impact. Joints undergo damage as forklifts traffic the joint area as wheel load and energy

Made available in DSpace on 2016-06-02T20:09:23Z (GMT). No. of bitstreams: 1 DissMAFS.pdf: 3260436 bytes, checksum: 90219abc927cfb10932082ff2066487a (MD5) Previous issue date: 2005-10-21 / The demand for simple and efficient solutions is increasing in civil construction, wherein the reduction of costs and the increase of speed and versatility within the applications are required. Due to its advantages, reinforced concrete ribbed slabs have been consolidated as an excellent alternative to compose buildings floors. The present research deals with this type of slab, disseminating its constructive characteristics, variations, structural behavior and the main recommendations proposed by different authors and addressing to all potential users (designers, constructors, contractors); recommendations, calculation methods to determine the internal forces and displacements, design and construction procedures according to the Brazilian code of practice NBR 6118:2003 are presented. Additionally, illustrative examples with the calculation, the detailing and the verifications of the serviceability limit state (crack width and extreme deformation) are presented. Finally, the results obtained from the examples simulating ribbed slabs in two directions are compared with the results obtained from the consideration of a massive slab. / A procura de soluções que sejam simples e ao mesmo tempo eficazes, tragam redução de custos, rapidez e versatilidade nas aplicações é crescente na construção civil. Em virtude de apresentarem uma série de vantagens, as lajes nervuradas de concreto armado têm se firmado como excelente solução para a construção de pavimentos de edificações. Neste trabalho aborda-se este tipo de lajes, divulgando suas características, opções construtivas, funcionamento e comportamento estrutural e as principais recomendações propostas por autores a todos os potenciais usuários (projetistas, construtores, proprietários); apresentam-se as ecomendações da NBR 6118:2003 que entrou em vigor recentemente, os processos de cálculo usualmente empregados para a determinação dos esforços solicitantes e deslocamentos transversais, roteiros com indicações gerais sobre o projeto e construção, e exemplos ilustrativos com o cálculo, o detalhamento e as verificações do estado limite de serviço (fissuração e deformação excessiva). Comparam-se os resultados obtidos simulando as lajes nervuradas armadas em duas direções como grelha com os obtidos admitindo-as como laje maciça.