Francisco de Paula Simões Lopes Gastal

Análise Teórico-Experimental de uma Laje Nervurada em Escala Natural

Nowadays, waffle slabs are a demand for structural designers, as a consequence of architectural design evolution and new building management concepts, in spite of its laborious numerical modeling. Therefore, it becomes necessary to know more about the structural behavior and improve the theoretical models used for simulating these slabs. The objective of this work was to analyze the adequacy of a design method widely used in the modeling of waffle slabs, verifying if it represents the slab behavior satisfactorily. A real scale waffle slab submitted to a load in a localized area was instrumented with strain gages and deflection gages for measuring specific strain and deflection in different points. The numerical analysis was made using a grid model developed by a local software company specialized in structural analysis. Tests showed a linear behavior, even though residual results could indicate cracking in some isolated sections. Numerically computed deflections presented a good estimate to test results and the experimental strains defined the presence of bending moments coincident with the forecasts of the theoretical model.

Numerical and Experimental Analysis of a Waffle Slab Parking Floor

AbstractRational and sophisticated structural solutions are essential requirements for structural designers, as a consequence of architectural design evolution and new building management concepts. Thus, waffle slabs turn out to be an interesting alternative, despite their laborious numerical modeling. It is necessary to increase knowledge about the structural behavior of and improve the theoretical models used for the simulation of these slabs. To better understand the behavior of RC waffle slabs, and more realistically quantify stresses and displacements of this kind of element under actual work conditions, a real-scale ribbed slab was tested and the results are presented in this paper. The chosen structure, designed to serve as a parking floor, was instrumented with strain and deflection gauges to assess the deformations and deflections developed under some induced loading conditions. A grillage model and a three-dimensional finite-element model were used for the numerical study. The data collected ind...

Numerical and experimental study of a waffle slab designed to serve as a tennis court floor

Reinforced concrete waffle slabs have become a common option for designers due to a need of rationalization in construction with reduction in costs and deadlines. To better understand the behavior of this structural system, and more realistically quantify stresses and displacements, a full scale waffle slab was tested. The structure, designed to serve as a tennis court floor, was submitted to a load of 12 kN/m2 and instrumented to measure strains and deflections at different locations. The loading process used the floors constructive base filling material and readings were taken at different loading stages and arrangements during the floors construction. Test data was compared to results obtained from the matrix analysis program Sistema Computacional TQS v11.0 and from the finite element model program SAP2000 v14.2.2. Slab behavior was as expected, with deflection and bending moments close to those determined by the numerical analysis.

Automatização da verificação de vigas em concreto com protensão aderente e não aderente, segundo as normas brasileira e francesa

Este artigo apresenta uma proposta para a automatizacao dos procedimentos de projeto de pecas fletidas de concreto com protensao aderente e nao aderente, conforme recomendacoes das normas brasileira (NBR 6118:2007) e francesa (Regles BPEL 91). E crescente a utilizacao da protensao em estruturas de concreto, devido principalmente as suas vantagens construtivas, a reducao na incidencia de fissuras e a diminuicao das dimensoes das pecas com o emprego mais eficiente dos materiais de maior resistencia. A analise estrutural e feita atraves de um modelo numerico que utiliza elementos finitos do tipo hibrido para porticos planos, considerando a nao-linearidade geometrica, carregamentos ciclicos e construcao composta. Nas rotinas computacionais implementadas sao consideradas as situacoes de protensao completa, limitada e parcial e verificados conforme cada caso, os estados limites de descompressao, de formacao e de abertura das fissuras, alem dos estados limites ultimos finais e no ato da protensao. Por fim, sao apresentados dois exemplos que comparam situacoes de projeto, segundo as normas brasileira e francesa.

Análise numérica de flexão em lajes nervuradas com a consideração dos efeitos de fissuração no concreto

Abstract Resumo Waffle slab structures simulated by computational model are generally analyzed by simplified methods, for both the section geometry (converting into solid slabs or grids) and for the material mechanical properties (linear elastic regime). Results obtained by those studies show large differ-ences when compared with test results, even at low loading levels. This is mainly due to lack of consideration of the eccentricity between the axis of the ribs and the cover, as well as the simplification of the mechanical behavior of concrete tensile strength. The so called more realistic numerical models do consider the effect of the eccentricity between the axis of the cover and ribs. One may also introduce physical nonlinearity of reinforced concrete in these models, obtaining results closer to tests.The objective of this work is to establish a numerical model for the typical section of waffle slabs given the recommendationslisted above. Such model considers the eccentricity between the axis of the ribs and the cover, the physical nonlinearity of concrete in compression and the concrete contribution between cracks (tension stiffening) through a smeared crack model. The finite element program SAP2000 version 16 is used for the non-linear analysis. The area element discretization uses the Shell Layered ele-ment along the thickness of layers, allowing for the heterogeneous material behavior of the reinforced concrete. The numerical model was vali-dated comparing results with tests in slabs and, eventually, used to evaluate some waffle slabs subjected to excessive loading.Keywords: waffle slab, reinforced concrete, numerical model, non-linear analysis.As estruturas de lajes nervuradas simuladas por modelo computacional geralmente sao analisadas por metodologias simplificadas, tanto para a geometria da secao (convertendo em lajes macicas ou grelhas) como para as propriedades mecânicas dos materiais (regime elastico-linear). Os resultados obtidos por estes estudos teoricos apresentam grandes diferencas quando comparados com os valores dos ensaios experimentais, mesmo para baixos niveis de carregamento. Isto se deve principalmente pela nao consideracao da excentricidade entre os eixos da nervura e da capa como tambem a simplificacao do comportamento mecânico do concreto a tracao. Modelos numericos chamados realisticos consideram o efeito da excentricidade entre os eixos da capa e da nervura da secao transversal. Pode-se, ainda, introduzir a nao-linearidade fisica do concreto armado nestes modelos, obtendo resultados proximos do experimental.O objetivo deste trabalho e estabelecer um modelo numerico para a secao tipica de laje nervurada que leve em consideracao a excentricidade entre os eixos da capa e da nervura, a nao-linearidade fisica do concreto em compressao e a colaboracao do concreto tracionado entre fissuras, atraves de um modelo de fissuracao distribuida. Utilizou-se o programa computacional de elementos finitos SAP2000 versao 16 para as analises nao-lineares. O elemento de area denominado Shell Layered permite considerar a heterogeneidade do concreto armado por discretizacao ao longo da espessura em camadas.O modelo numerico foi validado a partir de analises de lajes ensaiadas experimentalmente, comparando os resultados numericos com os dos ensaios. Tambem, este modelo foi utilizado para avaliar o comportamento pos-fissuracao de algumas lajes nervuradas submetidas a carrega-mentos excessivos.Palavras-chave: laje nervurada; concreto armado; modelo numerico; analise nao-linear.

Italian Heritage Building Technology in Pelotas

This survey is of the building techniques used by Italian builders and their descendants at the end of the 19th and beginning of the 20th century in Pelotas, a town in southern Brazil. The resultant economic growth from jerked meat production and the urban development of the town in this historical period encouraged the migration of European professionals. Among them were Italian sculptors, builders, and craftsmen who contributed to some of the main buildings but whose procedures were not documented. The economic and social development of a community require the restoration of the historic buildings. This research enabled the identification of building procedures and materials that were used by these builders in the buildings that still stand. In addition to providing the connection to those techniques and materials used in their country of origin at the time, this survey can be a future database for recovery, maintenance, and restoration work in these buildings.