Esta dissertação incide sobre a aplicação de uma técnica geofísica não destrutiva, designadamente o Ground Penetrating Radar (GPR), também denominado por georadar. Na componente prática deste trabalho são apresentados exemplos de aplicações utilizados para estudar as potencialidades do equipamento de georadar existente no Instituto Politécnico de Tomar. O GPR foi utilizado em dois solos, em pavimentos betuminosos, em duas paredes, em duas lajes de betão armado e numa ponte de alvenaria de pedra. Os resultados obtidos na aplicação do GPR em solos mostram que este equipamento é adequado para detectar a camada superficial de aterro. Em pavimentos betuminosos o georadar foi apropriado para descobrir a interface entre algumas camadas. Quando utilizado em paredes este equipamento permitiu identificar vazios, objectos no seu interior, detectar as armaduras, determinar o seu espaçamento e verificar o seu alinhamento. Na utilização em lajes de betão armado o GPR foi adequado para detectar as armaduras, determinar o seu espaçamento e verificar o seu alinhamento. No ensaio efectuado na ponte de alvenaria de pedra, o georadar permitiu determinar a espessura do lajedo, confirmar o centro do extradorso da aduela de fecho dos arcos (medidas na escala horizontal) e identificar algumas zonas com presença de humidade. O equipamento utilizado para aquisição dos dados foi o RAMAC/GPR da MALÅ Geoscience com as antenas blindadas de 250 MHz...
Even though the different sizes of cylindrical specimens for tests in concrete are
standardized to get the simple compressive strength and the modulus of elasticity,
this factor is not usually studied in most researches. So, the goal of this thesis was to
evaluate the influence of the size of the specimens in the initial tangent modulus of
elasticity (Eci) and in the compressive strength (fc), correlate the values of fc and Eci,
and compare the values of modulus of elasticity that were estimated by the equations
proposed by the Brazilian code (NBR 6118/2003) and by the American norm (ACI
Concretes with three levels of strength were used after 28 days: 25MPa, 30MPa and
40MPa. They were all proportionally mixed with materials of the region and supplied
by only one concrete batching plant of Goiânia GO. The tests of compressive
strength and initial tangent modulus of elasticity were done in cylindrical specimens
of 100 x 200 mm and 150 x 300 mm after 28 days. The samples were collected
during the delivery of the concrete in the construction sites. For each truck, ten
specimens were molded, five of 100 x 200 mm and five of 150 x 300 mm. Of the 600
specimens that were molded, 240 tests of compressive strength and 360 tests of
modulus of elasticity were done. The cure was in a tank with water saturated with
limestone. After the tests were done...
The objective this work is to develop and implement a methodology for special
inspection on Concrete Bridges trough the quantitative analysis of the degree of
deterioration of the structures so that it can serve as a basis for making decisions related
to the rehabilitation of these structures. In order to develop and apply the methodology
on concrete bridges, the existing methods of inspection of concrete structures were
studied and adapted to the adapting to the concrete bridges. The methodology was based
on GDE/UnB model in their latest formulation (Fonseca,2007) and adapted to the tables
with the elements to be analyzed, together with the pathological manifestations that can
occur in each element, timing and interventions classification of the level of
deterioration and the relevant factors to each family of concrete bridges. A pilot study
was proposed to validate the methodology. Results showed that there was a need for
further adaptation, to consider the caculations of the degree of deterioration of both the
family or the. With the changes proposed in the pilot study were made over 11 (eleven)
inspections in order to validate the proposed methodology. With the results obtained it
was concluded that the methodology for inspection of bridges is valid and of great
importance to public organisms and surveyors to make decisions about the best time and
the best item to be rehabilitated...
The structural behavior and the ultimate punching shear resistance of internal reinforced concrete flat slab-column connections, with one hole adjacent to the column, with or without flexural moment transfer of the slab to the column was investigated. Main variables were: the existence whether or not hole, flexural reinforcement layout and ratio, the direction and sense of the moment transferred and the eccentricity of the load (M (moment transferred to column) / V (shear)) ratio at the connection - 0,50 m or 0,25 m.
Seven internal slab-column joining were tested and ultimate loads, cracking, deflections, concrete and reinforcement strains were analyzed. The existence of hole adjacent to the smaller column dimension, the hole dimension, flexural reinforcement rate and placing, the variation of relation Mu/Vu in function of the load, and, than, of eccentricity of the load, influenced the slabs behavior and rupture load. These influences were quantified.
Test results were compared with the estimations from CEB-FIP/MC1990, EC2/2004, ACI-318:2005 and NBR 6118:2003. ACI and EC2 presented most conservative estimates, although have presented some non conservative estimates. Brazilian NBR, even though being partly based in EC2, presented smaller conservative estimates and more non conservative estimates. A modification on all codes is proposed for taking in account the moment caused by the eccentricity at the critical perimeter for slabs with holes.; São investigados o comportamento estrutural e a resistência última à punção de ligações laje-pilar de regiões internas das lajes lisas...
The use of concrete pavements in highways is a valuable alternative to obtain a
surface with high durability and low maintenance. This type of pavement has the
performance compromised by fissures, especially when they occur in the joint with greater
vulnerability of the concrete pavement. This work presents a study of the effectiveness of
sawed joints in concrete pavements where eleven plates were tested until failure. The
variables were: length of circular dowels (200 mm, 300 mm, 400 mm and 500 mm), dowel
diameter (10 mm and 16 mm) and type of concrete (conventional and self-compacting).
The tests were performed on the concrete plates supported on a base composed of sheets of
rubber. A line load was placed on one side of the joint. The test results showed that the use
of transfer dowels contributes significantly to the efficiency of the concrete pavements and
increasing the length and the diameter of the circular dowels improves efficiency; 10 mm
diameter dowels are not compatible with 120 mm thick concrete pavements, but 16 mm
dowels bars present good performance; the use of reduced dowel bar lengths below 40 mm
is not recommended; pavements with conventional concrete have better performance in the
joints due to better aggregate interlocking that the conventional concrete of this search
Eight reinforced concrete square flat slabs of reinforced concrete were tested.
Slabs were 130mm thick with an 1800 mm side and were submitted to central loading, and
the objective was to investigate the influence of column rectangularity coefficient. Column
cross section dimensions (cmáx/cmín) varyied between 1 and 4, with a constant perimeter equal to 1000mm.
Results presented and analysed include ultimate loads and failure types, modes of rupture, vertical displacements, cracking and deformations of steel and concrete. Comparisons
with codes, norms and results of literature results are also presented.
The results indicate that as the rectangularity coefficient increases, punching shear resistance decreases for constant perimeter column flat slabs. Suggesting that punching shear
has to be considered specially in regions close to column extremity, where there is a larger concentration of shear forces.
A proposal for an inclusion of the retangularity parameter (cmáx/cmín) in expressions for calculation punching shear resistance of ACI (2002), CEB-FIP (1991), EC2 (2001) and NBR-6118 (2003) codes is presented.; São analisadas experimentalmente 8 (oito) lajes cogumelo de concreto armado quadradas com 1800 mm de lado e 130 mm de espessura...
In a composite system, a steel beam (laminated, welded or cold formed) is associated with a
concrete slab, forming a composite beam. The interaction between concrete and steel can be
mechanical, by friction or, in some cases, only by adherence. One of the major advantages of
the composite beams is the increase in strength and stiffness due to association of steel and
concrete that makes possible the reduction of the height of the structural elements, implicating
in material economy. The present research has the purpose to present a general vision of the
structural behavior of the composite steel-concrete beams and to proceed to a more detailed
study of the behavior of the shear connectors made from cold formed steel. A modeling study
of the push-out test is accomplished with the intention to find the factors that influences the
resistance and rigidity of the connection. The numerical study consists in the elaboration of a
three-dimensional numerical model to simulate the push-out test from which is obtained the
force-displacement curve, ultimate load, deformations and tensions along the connector. The
numeric results are compared with obtained experimental values of rehearsals accomplished at
laboratory for validation of the same ones. For the accomplishment of the numeric modeling
the computational program ANSYS® 6.1 was used...
The increasing demand for aggregate for uses in engineering stimulated the search for
alternative materials. In this way, the civil construction potentially started to be a great
consumer of residues from other industries, becoming a great recycle plant.
The use of by-product, brings great environmental benefits in relation to the degradation of
the environment, as for example, less settlement of residues in earth fill, the reduction of
extraction of natural resources, and the exploration of aggregate ores.
Steel plants from around the world have a commom problem, that is what to do with all the
steel slags generated as a by-product from the steel refining in electric steel plants or
oxygen steel plants. There are two points of these process where slags can be generated:
the first comes from the electric or oxygen furnace itself (called oxidizing refining) and the
second is the laddle metallurgy slag (reduction refining slag), which is the last stage of the
This aims to demonstrate related studies to the use of steel slags (EAF slags) in electric
steel plants as coarse aggregate.
Expansibility of the steel slag tests had been carried through, compressive strength, tensile
strength for diametrical compression, related modulus of deformation and durability tests...
Many problems involving cases of ruins of buildings, bridges, etc., specifically ruin of columns, which are among the most important links in the whole structure, due to project flaw, bad execution or even for the evolution and changing habits. Therefore it has been of fundamental importance researches on the experimental behavior of structures. When conducting a strengthening column using dry with increased self-compacting concrete, it has the drawback of a sudden rupture by peeling the reinforcement. For this, there is a need to study the area of adhesion between substrate and to strengthen and create a way of preparation of this interface area so that the column increases may come into ruin in a ductile flexural as well as in a monolithic column. Thus, it s been developed an experimental study in the School of Civil Engineering, Federal University of Goias, based on analysis of the breaking loads, lateral displacements and deformations of the column of materials for different ways of preparing the surface of the column to be strengthened. The experimental phase of this work was based on testing of nine reinforced concrete columns, which are tested under flexural
compression, with eccentricity of 60 mm. Two columns were used as reference columns...
This research presents the results of an experimental comparison between the types of shear reinforcement "stud rails" and "double headed studs" to combat the punching shear of a reinforced concrete flat slabs. It also presents a comparison of experimental results with those provided under the ACI 318/2005, CEB-FIP MC/1990, EUROCODE 2/2004 and NBR 6118:2003. The motivation was to investigate the efficiency of these shear reinforcement for the differences between them.
It was tested six slabs of concrete to concentric load, with dimensions of 2400 mm x 2400 mm x 150 mm. It was concreted a column of section 500 mm x 200 mm to 850 mm total height next to the slab. The main variables were the type of shear reinforcement "stud rails" x "double headed studs, the "studs" diameter and the shear reinforcement area per layer. The slabs were tested until the failure.
It was monitored the deflection, reinforcement deformation of bending and shear. All slabs failed by punching with internal surface rupture. The experimental results after being compared with the expected standard in each individual calculation showed conservative values.
Slabs of Group 1 with "stud rails" presented failed loads greater than those in Group 2 with "double headed studs. Codes/standards 318/2005 ACI...
In the case of conventional concrete, small constructive defects, variations of mix proportion or even inadequate curings can not compromise significantly the material. No
longer HPC demands a severity in the control since its dosage until the execution, therefore any imperfection can bring serious damages to the material or the structure. Amongst the relative aspects most important to the total quality of any concrete it is the curing, that becomes basic when is about HPC. The curing of the high performance concrete constitutes in a controversial subject in the technician area as well as the type and duration of it, therefore the necessity of a deeper refined study on this subject. This research verifies the influence of the type and time of duration of curing in the mechanical properties of the HPC (compressive strength, flexion tensile strength and module of deformation), produced in Goiânia in hot period (t>25ºC) and of low relative humidity of air (h<50%) situation this considered critical for NBR 14931/2003 and predominant in the months of May the September in this region. In the experimental study were produced HPC of target compressive strength 60, 80 and 100MPa, from the Furnas Mix Proportion Method, using cement CP II-F-32...
The main objective of this research is to proceed to the rising of the indexes, to identify the pathologies and to characterize the constructions that presented occurrences of pathological manifestations in foundations and structures in the
constructions executed in the State of Goiás, with age of up to ten years. The researches was classified as documental, considering that, to make possible the accomplishment of the same, the files of Regional Council of Engineering, Architecture and Agronomy of Goiás were analyzed -Crea/GO, with a total sample of 545 reports. It was observed that most of the processes are concerning the last seven years. This Organ was chosen by the fact that all of the technical documents are elaborated by professionals, and, mainly, for
Official Organ to be considered. The Method of the Incidence was adopted as methodology recommended for this study observing that in the reports and decisions, elaborated by Crea-GO doesn't be in the number of occurrences of a same pathology and yes only the incidence of the same. The main conclusions of this research were: the main pathological manifestation was found in the foundations repression with a rate of 37.50% followed by collapse with a rate of 22.50%, both in relation to all the pathologies found in the foundation stage...
Due to the small number of studies about the process of production of the concrete dosed in central, as regards the type of employed mixture, this inquiry looked to contribute to the assessment of quality of concrete produced in mixing plant and metering plant. The principal objective of the work was checking if the form of mixing of the concrete can affect your characteristics in hardened state (compressive strength), for that, there was compared the quality of the concrete produced in metering plant and mixed in truck mixer in relation to the mixing plant. As the sample was taken a work, where they had installed a metering plant and a mixing plant, which together produced 300.000 m³ of concrete with the same materials. Inside the proposed objective, also were quantified statistically the existent types of concrete in the same truck mixer, using as the parameter the compressive strength of concrete produced in the metering plant.
In the end, it was possible to conclude that the mixing plant produce a concrete of better quality with a less standard deviation than the metering plant. Was also observed a significant variability inside the truck mixer, which made the division of the concrete possible in five group, with different resistances'; Em razão do pouco número de estudos relacionados ao processo de produção do concreto dosado em central...