Felipe Nascimento Arroyo

Technical Feasibility Study for the Use of Alternative Timber in Latticework for Roofing with Spans between 16 and 26 Meters

Wood, a renewable source material, has been part of the progress of mankind, being widely used in construction for centuries. However, with the passage of time, new construction techniques were being applied, new materials have been rising and, in the meantime, wood was being left out, being labelled as a material with huge incidence of pathologies. That due to its empirical use without any technical knowledge regarding its physical and mechanical properties, which still happens nowadays, being used mainly for temporary purposes. In order to show the technical viability of the use of this material as a structural element, the elaboration of projects with the following characteristics was proposed: buildings with truss structures (parallel chord) type Howe (10° inclination - steel tile); 16, 18, 20, 22, 24 and 26 meters span; side openings types of the building – 1:1, 2:1, 6:1 and open; preservative treatment. Thus, it was determined the ratio of the volume of wood (m³) and the built area (m²) for timbers classes C-20 and C-30, following the NBR 7190:1997 guidelines. With the results, it is possible to assure the real possibility of using wood species C-20 and C-30 as structural material.

Pull Out Strength of Bonded-in Steel Rods Perpendicularly to the Grain in Corymbia citriodora and Pinus oocarpa Shiede Timber

The study of pull out strength of glued in rods perpendicularly to the grain is presented. Three types of resin were used in order to evaluate their efficiency. Additionally, the effects of the variation of the moisture content and of the glue line thickness were considered. The beams were made of wood from Corymbia citriodora, (ρ12% = 1000 kg/m3) and Pinus oocarpa Shiede (ρ12% = 550 kg/m3). The wood specimens (four samples for each type of test) were seasoned to the expected moisture contents of 12, 15, 18 and 22%. The anchorage length of the glued in rods was 80 mm, the hole diameters were 7.5, 8.5, 9.5 and 10.5 mm and their respective glue line thickness, 0.6, 1.1, 1.6 and 2.1 mm. The deformed reinforcing bars used as rods, with the minimum yield strength of 500 MPa, had nominal diameter of 6.3 mm. The obtained results confirmed the assumption that type of resin, moisture content, glue line thickness are strength determining factors, while density is less than others. The results are presented in a comparative form. The failure modes are discussed and the need of a broad understanding of resin behavior on wood was emphasized.

Pull Out Strength Evaluation of Bonded-in Steel Bars in Pinus oocarpa Shiede Structural Members

The connections with bonded-in steel bars present excellent aesthetics, trustworthy performance, high strength and stiffness, and are more economic compared to the equivalent traditional mechanical connections. Nonetheless, their use in an economic and safe way depends on the deeply knowledge about influences on the pull out behaviour and on many different connection work conditions. Among these parameters, it can be pointed out with great relevance, the diameter variation of the bars used, which influence directly on the adherence surface on the anchorage area. In this work, the experiment was conducted in order to evaluate the effects of steel bar diameter variations of bonded-in with the epoxy resin Compound, in three directions (0, 45and 90o) between the rods and the wood fibers. The wood natural variability was considered through random sample of a batch of structural Pinus oocarpa Shiedetimbers. In each observation, with a total of seven combinations of variables, six replications were presented. The steel bars used were highly stiffness ones (CA-50), with threaded surface solicited into the axial direction under monotonic loadings, with two consecutive load cycles. Thereafter statistical analysis, the results are presented and commented in a comparative way.

Determination of the Sliding Modulus and Limit Strength of Shear Connectors for Mixed Wood-Concrete Structures

Tests with specimens are still the most suitable way in order to get to know the mechanical and elastic behavior of shear connectors, which are used in mixed wood-concrete structures. The most used wood-concrete specimens are the symmetrical push-out type models. About the great diversity of connectors, considering type, stiffness, strength value and their position in the structural member, besides other varieties as: spaces between connectors, dimension variation and mechanical and elastic properties of the materials involved, several normative standards suggest that the wood-concrete specimens shall represent the real connection behavior. In Brazil, due to lacking of normative procedures, plenty of wood-concrete specimen models and criteria have been used for the determination of the limit strength and the slip modulus of these connections. In this paper some wood-concrete specimen models are presented, they were suggested in some normative documents and others presented into the international literature and national research. Some procedures are suggested for obtaining the slip modulus and limit strength, representing the real conditions of the connection.

Forces in Bracing Elements of Timber Trusses

This book deals with the analysis of the forces acting in bracing of triangular timber trusses of warehouses roofings by computational numerical models based on the Finite Element Method (FEM). Were used the structural analysis software STRAP and consider the operation of bracing in the three-dimensional structure. The maximum force values obtained in the three-dimensional models were compared to the minimum values indicated by the estimation method of the Brazilian standard ABNT NBR 7190:1997, which is based on the lateral instability of the braced element. The values of three-dimensional models are also compared to the methods of Eurocode 5, the South African Standard SABS 0163 and the values proposed by UNDERWOOD (2000), by presenting a similar formulation to the NBR 7190:1997. The models represent usual warehouses with dimensions ranging from 12, 18 and 24 meters wide, 24, 48 and 96 meters length, and 3, 4 and 6 meters column heights. In this context, were analyzed the trusses types: Pratt and Howe, the timber classes: C30 and C50 and the roof types: fiber cement, metal sheets and ceramics tiles – materials most used in Brazil.

Development of Alternative Simulator for the Sugar Manufacturing Process

This research has the proposal create a simulator to valuate and simulate the capacity of a sugar factory, supporting the strategic decision making process. The process of creating simulator starts when processes are mapped and all most important variables are defined. After that it was necessary to transmit measured data through the calculations for spreadsheet, which in this case was used Excel (because it is a simple language and a common program). In sequence, several tests were performed to check results obtained by simulation. The results refer to the simulator reliability, with comparison of SIMULSUGAR results with simulation conducted in sector. Creating a table was necessary to demonstrate the accounting comparison between SIMULSUGAR results with simulation performed in the sector.

Characteristics Value Estimate of Steel Bar Anchor Strength by Mean Response Confidence Interval

The statistical experiment design is an indispensable tool to the searching front the multivariable situations. Whichever the design statistical adopted or simply response of random variables, the technique of multiple regression for situations with normal distribution can be used to determine or to develop more adequate the statistical model. This model allows to infer on the experimental data. The estimates of the mean response of this model sufficiently are used in real applications of project, however in the structural applications the estimate of the response in the 5% down percentile is necessary, called characteristic value of the response. In this research, present the experimental strength results of bonded-in steel rods in timber in angle 45o between the rod and the direction of the grain, the estimates of the mean strength by analysis of multiple regression, the confidence interval of 90% and the characteristics response. The independent variables were used: anchorage area of steel bar surface, moisture of the wood and density. All combination of variables presented were six replicate. The wood used was Corymbia citriodora, dry to the air, with CCA treatment; were used galvanized threaded steel bars CA-50 and compound adhesive gel epoxy resin. This research results in the mean anchorage force, response of the analysis of multiple regression, the determination of the confidence interval and the estimate of the characteristic values for the variables combination, in the edges and inside of the interval of the experiment.

Cracks Studies Case of Buildings in Sinop City - Brazil

The building structures are objects of interest in Civil Engineering, appropriate to its importance in sustaining and preserving the building. The monitoring of their behavior can occur for analyzes on structural elements, directly, or other structures for monitoring the building. Such situations encourage the improvement of new techniques for structural evaluations through measurement service elements and interpretation of monitoring data. Amid this context, the present study aims to analyze, diagnose, classify, expose the possible causes and possible solutions of the problems of the buildings studied pathological located at Sinop – MT, where the study included various types of buildings from earthen, 3, 11 e 19 pavements, as residential construction, public and private educational institutions, or for use in the construction step, all intuited with the larger scope of diseases in the municipality, identifying whether or not problems that could compromise the safety criteria, resistance and good performance of buildings.