KIRCHHOF, L.D. (2004). A contribution to the study of simply-supported composite steelconcrete beams in ambient temperature and in fire situations. São Carlos, 2004. 143p.

O presente estudo descreve uma nova concepção geométrica para os blocos de concreto não modulares especialmente concebidos para alvenaria estrutural, com montagem capaz de permitir a superposição das paredes longitudinais e transversais dos blocos nas diferentes fiadas da parede, para facilitar o grauteamento e o posicionamento das armaduras verticais dos elementos estruturais. O conjunto de blocos possuem geometrias específicas para cada função, o que facilita a execução das alvenarias armadas e o aumento no desempenho estrutural e a produtividade Como geometria final, desenvolveu-se um conjunto não modular de unidades com potencial de atender aos objetivos do sistema construtivo em alvenaria estrutural.

In this paper, an experimental program was carried out to investigate the residual mechanical properties of high strength concrete and normal strength concrete, and how moisture content and temperature affect the spalling process. Three mixtures with water-cementitious material ratios, from 0.25 to 0.50, and with different saturation levels were heated in an electric furnace to elevated temperatures, from 200°C to 600°C. After heating, the specimens were cooled down to room temperature and then tested for compression and tensile strength. The results showed that high moisture content induces the spalling process and reduces considerably the mechanical properties of high strength concrete, mainly at temperatures above 400°C.

ResumoNeste trabalho são propostos modelos numéricos tridimensionais de vigas mistas aço-concreto simplesmente apoiadas, considerando-se apenas a interação total (desconsideração de deslocamentos relativos entre laje de concreto e viga de aço). Os modelos são construídos com vistas a simular o comportamento de vigas mistas, em temperatura ambiente e em situação de incêndio, utilizadas na prática da construção. Utiliza-se, para a modelagem numérica, o programa ABAQUS versão 6.3-1 elaborado com base no Método dos Elementos Finitos. Os resultados numéricos obtidos são comparados com resultados experimentais apresentados por outros pesquisadores. Os resultados numéricos, quando comparados com resultados experimentais, demonstram que os modelos elaborados com elementos finitos do tipo casca apresentam melhor desempenho quando comparados com os modelos elaborados com elementos finitos do tipo sólido. Palavras-chave: Estruturas Metálicas. Vigas Mistas Aço-concreto. Incêndio. Análise Numérica. AbstractThis paper presents three-dimensional numerical models of steel-concrete composite beams with full interaction (no slip between concrete slab and steel beam) using a non-linear procedure. The threedimensional numerical models must be capable of predicting the response of composite beam at ambient temperature and in fire situation with accuracy. The computer program ABAQUS ® 6.3-1, based on Finite Element Method, was used to analyze the numerical modeling. The accuracy of the models is demonstrated through the results obtained, which are compared with the experimental results presented in other works. The reported results, when compared to experimental data, demonstrate that the numerical models elaborated with shell finite elements show better performance when compared to the results of the numerical models elaborated with solid finite elements.

The rice in the south of Brazil is one of the main economy activities, which produce a large volume of waste coming from the beneficiation industries. The main goal of this research is evaluate the feasibility of use of rice husk ash, burning on fluidized flow (FF) and sliding grid (SG) for mortars. The characterization methods of rice husk ash (RHA) included loss on ignition, particle size distribution by laser, x-ray diffraction, x-ray fluorescence spectrometer, pozzolanic activity index and specific mass. Mortar specimens were molded with the proportion of 1:3 in mass and water/binder ratio of 0.51. The Portland cement was replaced by RHA with the proportion of 10%, 15% and 20%. Compressive strength, water absorption, air voids content, hydration-releasing heat curves, mercury intrusion porosimetry and scanning electron microscope were performed for all mortars. The mechanical performance of mortar with RHA replacement, shows to be satisfactory and feasible alternative for the final waste disposal.