Dissertations / Theses on the topic 'Column interaction diagrams'

CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO
A utilização do concreto de alta resistência já é uma realidade e muitos países estão adaptando suas normas para levar em conta as propriedades deste material. No dimensionamento de pilares esbeltos e seções com concreto de alta resistência é importante observar a relação tensão- deformação adotada no cálculo, pois enquanto para o concreto convencional a deformação máxima, ecu, é 0,0035, para o de alta resistência esta deformação depende do valor da resistência do concreto, diminuindo com o aumento do fck. Para um concreto com fck = 80 MPa, por exemplo, ecu é em torno de 0,0022 de acordo com as relações tensão - deformação propostas pelo MC90-CEB. A relação tensão- deformação com ecu dependente de fck irá alterar os diagramas de interação adimensionais para o dimensionamento de pilares esbeltos e concreto de alta resistência. São construídos neste trabalho diagramas de interação força normal - momento fletor - curvatura (n,m,f) e força normal - momento fletor - índice de esbeltez (n,m,l) para o dimensionamento de pilares esbeltos e diagramas de interação (nd,md) e (nd,mdx,mdy) para o dimensionamento de seções submetidas a flexão composta reta e oblíqua. Adotou- se a relação tensão-deformação proposta pelo MC90-CEB e valores de fck de 50 a 80 MPa. Os diagramas para pilares esbeltos foram construídos com auxílio do programa PCFRAME (KRÜGER, 1989) e os diagramas para o dimensionamento de seções foram construídos com um programa desenvolvido neste trabalho. Através dos resultados, observa-se que, como ecu depende de fck, todos os diagramas de interação sofreram diferenças, podendo ser dito ainda que o uso dos diagramas já existentes, construídos com ecu constante e igual a 0,0035, pode conduzir a erros contra a segurança estrutural.
The use of high strength concrete is already a reality and many countries are adapting their design codes to take into account the properties of this material. For the design of slender columns and sections subjected to combined axial force and bending, the most important property is the stress-strain relationship. While for normal concrete the strain at ultimate, ecu, can be considered constant and equal to 0,0035, for high strength concrete ecu depends on the concrete strength, decreasing as the strength increases. For a concrete with fck of 80 MPa, for instance, ecu is around 0,0022 according to the CEB Model Code (1990). Stress-strain relationship with ecu dependent of fck will affect the nondimensional interaction diagrams for the design of slender columns and sections of high strength concretes. Nondimensional interaction diagrams moment-axial load-curvature (m,n,f) and diagrams moment-axial load- slenderness ratio (m,n,l), for the design of slender columns, and nondimensional interaction diagrams (md,nd) and (nd,mdx,mdy) , for compression plus axial and biaxial bending of sections, are constructed in this work. The diagrams were constructed for concretes with strength between 50 MPa and 80 MPa, adopting suitable stress-strain relationships recommended by the CEB Model Code 1990. The diagrams for slender columns were constructed with the aid of an existing computational program developed in an earlier thesis, while the diagrams for the design of sections were constructed with a new program, specially developed in this work. The results have shown that all these diagrams are affected, even when presented in a nondimensional form, when stress-strain diagrams with ecu dependent of fck are adopted. The use of traditional nondimensional interaction diagrams, constructed with ecu constant and equal to 0,0035, may lead to errors against structural safety.
La utilización del concreto de alta resistencia es una realidad actual y muchos países estan adaptando sus normas para tener en cuenta las propiedades de este material. En el dimensionamiento de pilares esbeltos y secciones con concreto de alta resistencia es importante observar la relación tensión-deformación que se adopta en el cálculo, porque mientras para el concreto convencional la deformación máxima, ecu, es 0,0035, para el de alta resistencia esta deformación depende del valor de la resistencia del concreto, diminuyendo con el aumento del fck. Para un concreto con fck = 80 MPa, por ejemplo, ecu es en torno de 0,0022 de acordo con las relaciones tensión - deformación propostas por el MC90-CEB. La relación tensión- deformación con ecu dependente de fck alterará los diagramas de interacción adimensionales para el dimensionamiento de pilares esbeltos y concreto de alta resistencia. En este trabajo se construyen diagramas de interacción fuerza normal - momento flector - curvatura (n,m,f) y fuerza normal - momento flector - índice de esbeltez (n,m,l) para el dimensionamiento de pilares esbeltos y diagramas de interacción (nd,md) y (nd,mdx,mdy) para el dimensionamiento de secciones sometidas a flexión compuesta recta y obliqua. se adoptó la relación tensión-deformación propuesta por el MC90-CEB y valores de fck de 50 la 80 MPa. Los diagramas para pilares esbeltos fueron construidos con auxilio del programa PCFRAME (KRÜGER, 1989) e implementamos un programa para obtener los diagramas para el dimensionamiento de las secciones. A través de los resultados se observa que, como ecu depende de fck, todos los diagramas de interacción sufren diferencias, y puede decirse que el uso de los diagramas construidos con ecu constante e igual la 0,0035, pueden conducir a errores que afectan la seguridad extructural.

The influence of the recommended LRFD Guidelines for the seismic design of highway bridges in Virginia was investigated by analyzing two existing bridges. The first bridge has prestressed concrete girders and is located in the Richmond area. The second bridge has steel girders and is located in the Bristol area. The analysis procedure for both bridges is similar. First the material and section properties were calculated. Then the bridge was modeled in RISA 3D. Live and dead load were imposed on the bridge to calculate the cracked section properties of the bridge. The period of vibration of the bridge was also calculated. After the soil class of the bridge was determined, the design response spectrum curve of the bridge was drawn. The spectral acceleration obtained from the design spectrum curve was used to calculate the equivalent earthquake loads, which were applied to the superstructure of the bridge to obtain the earthquake load effects. Live and dead loads were also applied to get the live and dead load effects. The combined effects of the dead, live and earthquake loads were compared to the interaction diagram of the columns and moment strength of the columns. The details of the bridge design were also checked with the corresponding seismic design requirement.A parametric study was performed to explore the effects of different column heights and superstructure heights in different parts of Virginia. The column longitudinal reinforcing was increased to satisfy the bridge axial loads and moments that are not within the column interaction diagram.
Master of Science

The diploma thesis deals with the strenghtening of the supporting parts of the production hall in Drásov. In the first part the existing load bearing capacity of the structure is solved. The next step is to design of strenghtening variants for nonconforming columns and short corbel. Columns and short corbel are strenghtening with monostrand. At the end of the thesis, verification of the load bearing capacity of the strenghtening structure is performed.

The aim of this thesis is to design a load-bearing structure for the ultimate and serviceability limit state of a civil building. The structure is designed as a cast-in-place concrete structure, composed of columns and floor slabs. The building has total of 5 floors, two are under-ground and three above-ground. The thesis contents of a structural design and design options, structural design report for load-bearing elements, processing of the drawings, details, visualizations. Internal forces calculation is carried out in SCIA Engineer and validated by the moment accumulation method for slabs. The columns are assessed by interaction diagrams, one is verified by hand calculation. The resulting internal forces are taken from the computational programme. Foundations are not subject for solution.

The thesis is focused on the design and assessment of selected elements of load-bearing structure of hospital pavilion. This pavilion consisted of board frame with additionally lined self-supporting perimeter cover. Selected elements of the structure are locally supported slab, columns, foundation pad and staircase . Computational model was assembled of the software RFEM5. Internal forces locally supported slab were verified by manual calculation. The design documentation consist of engineering report, structural analysis and shape and reinforcements drawings of selected structural elements.

The content of the thesis is a static design of the supporting parts of the extension of the textbook pavilion of the elementary school in Mirošov. The proposed building is a four-storey reinforced concrete monolithic column construction. The ceilings above the first three floors are designed as cross-reinforced slabs with internal girders. The roof slab consists of a monolithic slab with additionally prestressed beams. The internal forces were calculated using SCIA Engeneer 19.0 and these values were subsequently verified by manual calculation. The design followed the applicable European standards. The result of the work is a static assessment of the object and corresponding drawing documentation.

The final thesis is focused on reworking hospital pavilion from cast-in-place structure to precast concrete frame. Calculation of internal forces is made by software system SCIA Engineer. Main load-bearing elements are inner beam, outside beam and all columns in axis 2-C. This thesis contains assembly report, structural design, calculations and drawings of the designed parts, joint details, assembly material drawing and hand calculation.

Strengthening of reinforced columns confining by modern composite materials is effective method, allows quickly realized strengthening, without increase dimension of strengthening columns. Just like using reinforcing bars, is the mainly assumption for this method the multi-axis state tension and deducing confining pressure, which will increase strength of concrete. Improved of properties of confining concrete can be determined by using relationships, but there are considerably differences. This diploma theses, dealing with strengthening of circular reinforced columns confinement by external FRP fabric, compared approaches to design of reinforced concrete by confining and using the results of an analytical and numerical study to describe problem of confining concrete and compare factors influencing the final properties of the wrapped concrete.

This diploma thesis deals with design and assessment of selected parts of the reinforced concrete frame of multi-storey administrative building according to the ultimate and serviceability limit state. The aim of this thesis was to design and assess the reinforced concrete structure of a slab above the first floor, one column, a foundation pad and a staircase. In addition to the static calculation, drawing documentation is included. Internal forces were obtained from the 3D model created in computational software Scia Engineer 16.1.

This diploma thesis focuses on the design of roof slab in two options. Internal forces are calculated by software rfem. The thesis also includes design of column, manual calculation and comparision with finite element method and drawings.

The aim of diploma thesis is a design and an assessment of selected structural elements of one floor in monolithic concrete structures serving as covered parking for an apartment house. Software RFEM is used here to calculate internal forces. The thesis also includes manual calculation of internal forces and comparison with software results. It also includes drawings of proposed solution. All calculation are done in accordance with Eurocode 2.

The steel bandage is an economical and effective widely used method for strengthening RC columns. Diploma thesis reviews most common design proposals for the types of the bandage with directly loaded and not directly loaded steel angles. This work also includes a comparison of the different constitutive laws for confined concrete. In order to simulate real behaviour of strengthened structure the numerical analysis has been carried out using non-linear software ATENA. According to the European standards and adopted hypotheses the simplified analytical model has been derived to be able to calculate load-bearing capacity of a strengthened column under normal force and bending moment. The proposed model considers the contribution in confinement pressure caused by steel bandage and the contribution of directly loaded angles. In addition, the direct application on real frame structure has been performed.

The diploma thesis is focused on design and assessment selected parts of the reinforced concrete structure supporting six storey office building with regard to the ultimate and serviceability limit state.This thesis contains a static calculation and technical drawings of concrete slab above first floor, staircase and two columns. For calculation of internal forces was created a 3D structural model in Scia Engineer 16. Assessment of all designed parts of the structure is done according to Eurocode 2 (ČSN EN 1992-1-1).

The diploma thesis is focused on the design and review of selected load-bearing elements of the precast hall. Girder is dimensioned in two variants: reinforced and prestressed concrete. Design and assessment of prestressed girder was carried out using the simplified method and the IDEA statica. Column and footing was also dimensioned. All calculations are done in accordance with Eurocode 2.

The diploma thesis is focused on design on loadbearing reinforced concrete structure of multi-storey apartment building with shops and offices on the ground floor and underground garage. The thesis consists of the analysis and design of ceiling slabs above underground floor, supporting columns and the beam under the underground floor ceiling slab. Calculation 3D model was created to determine internal forces. All structures are designed according to EC2, ČSN EN 1992-1-1. The thesis includes elaboration of static calculation, shape drawings, drawings of reinforcement of solved structures. The rest of the project part are not analysed.

The diploma thesis is aimed for design and assessment main load bearing elements of a apart-ment building on the ultimate and serviceability limit state. Assessed parts of construction are reinforced concrete slab over the second floor, column and shear wall in the first floor, stairway slab and foundation pad. The elements are assessed in a structural design report according valid standard. There is created drawings. Internal forces are calculated using software Scia Engineer, where is modeled and loaded the construction.

As the main topic this thesis describes the design and evaluation of selected reinforced concrete members of the prefabricated reinforced concrete industrial building with administration at ultimate limit state in accordance with applicable standards. Movable overhead crane with carrying capacity of 50 tons is the main distinction of the industrial hall. Lateral frame whit main structural parts which are roof prestressed girder, load-bearing column supporting the overhead crane and drilled pile transferring loads from the upper construction to the load bearing subsoil, is designed in particular. Furthermore, design of the Gerber beam which forms the slab construction in the administrational part of the building is elaborated. Structural design and evaluation of other structures of the building is not part of this thesis.

碩士
國立臺灣科技大學
營建工程系
105
To address the need for high-rise reinforced concrete buildings in Taiwan, Taiwan New High-Strength Reinforced Concrete (Taiwan New RC) project was initiated. The project integrates the resources of academia and industry of Taiwan to develop the New RC structures for use in Taiwan. The longitudinal and transverse reinforcement used in the project are SD690 (yield strength of 685 MPa) and SD790 (yield strength of 785 MPa), respectively. The concrete compressive strength is typically ≥ 70 MPa. This research have developed a computer program for axial load-moment (PM) interaction diagram for new high-strength reinforced concrete(NewRC) columns which named “NewRC-PM”. In addition to calculating PM interaction diagram, NewRC-PM has been programmed to anlysis the moment-curvature relationship of reinforced concrete column. The theoretical background and verification of the New RC-PM are presented and discussed in this thesis. Moreover, a test database with 297 rectangular columns which including 173 columns using high strength concrete were established . New RC-PM was used to analyze the PM interaction diagrams of the columns in database.The estimation of columns which using high strength concrete has compared with the test results.The comparison showed that the New RC-PM only gives 2 unconservatively estimation for the axial-bending strengths of those 173 columns.However,the procedure specified by current building code to calculate the axial-bending strengths gives 13 unconservatively estimation for those 173 columns which proves that the New RC-PM could more conservatively estimate the axial-bending strengths of the columns. This research further evaluate the ratios of maximum moment strength to nominal moment strength. Evaluation results showed that this ratio significantly increases as the axial load ratio increases. This research derive the mathematical formulas to prove that confinement effect of concrete can cause this phenomena.A simple formula for calculating the maximum probable moment strength (Mpr) which consider this phenomena has been proposed. Moreover, the simple formula is used to calculate the maximum probable moment strength of columns of database. Evaluation results shows that the Mpr calculated by the simple formula more conservative than the method of the current building code and the current bridge code. A more detailed method which using moment-curvature relationship to calculating the Mpr also proposed in this research. The evaluation result shows that the accuracy of this detailed method slightly less than the method of the current bridge code. However, this detailed method give the lowest coefficient of variation compared with the other three method .