11 |
Nonlinear seismic response of wall-frame structuresPetalas, Nicholas. January 1979 (has links)
No description available.
|
12 |
An experimental investigation of the behaviour of connections in thin precast concrete panels under earthquake loadingKallros, Mikael Kaj January 1987 (has links)
Investigations of connections for precast concrete panel buildings have shown that it is difficult to design an embedded connection that will perform well under earthquake loading. Some typical connections use studs or reinforcing bars embedded in the edge of the panel. These are then welded or bolted to an adjacent panel. During earthquake loading the crushing of concrete around the embedment usually leads to premature loss of strength and stiffness of the connection before significant ductility can develop. It has been found that connection performance improves with increasing panel thickness.
The behaviour of embedded connections in thin precast concrete panels was investigated. The intent was to improve connection design details and to develop a simple method of predicting connection strengths with panel thicknesses of 50 mm to 75 mm.
Sixteen connections of six different types were tested. Three were tested monotonically and thirteen were tested under reversed cyclic loading.
Certain types of connections can be used to transfer earthquake loads between thin concrete panels as long as they have adequate strength. Methods for predicting the strength of connections are discussed. The connections tested should not be relied on to develop ductility. / Applied Science, Faculty of / Civil Engineering, Department of / Graduate
|
13 |
Seismic design of friction damped braced steel plane frames by energy methodsFiliatrault, Andre January 1988 (has links)
The investigation described in this thesis represents the first known attempt to develop a simplified method for the seismic design of structures equipped with a novel friction damping system. The system has been shown experimentally to perform very well and is an exciting development in earthquake resistant design. The design of a building equipped with the friction damping system is achieved by determining the optimum slip load distribution to minimize structural response.
A new efficient numerical modelling approach for the analysis and design of Friction Damped Braced Frames (FDBF) is presented. The hysteretic properties of the friction devices are derived theoretically and included in a Friction Damped Braced Frame Analysis Program (FDBFAP), which is adaptable to a microcomputer environment. The optimum slip load distribution is determined by minimizing a Relative Performance Index (RPI) derived from energy concepts.
The steady-state response of a single storey friction damped structure subjected to sinusoidal ground motion is investigated analytically. Basic design information on the optimum slip load for the friction device is obtained. The parameters governing the optimum slip load, which minimizes the amplitude for any forcing frequency, are derived. The study indicates that the optimum slip load depends on the characteristics of the ground motion and of the structure.
Using variational principles on a shear beam analogy, an optimum slip load distribution along the height of the structure is derived when the total amount of slip load is specified. It is shown that the optimum slip load is proportional to the slope of the deflected shape of the structure. The results of the study reveal that only a small improvement in the response is obtained by using this optimum distribution
compared to the response obtained with a uniform distribution. Therefore the use of an optimum uniform distribution seems adequate for the design of friction damped structures.
Taking into account the analytical results obtained, FDBFAP is then used in a parametric study which leads to the construction of a design slip load spectrum. The spectrum depends on the properties of the structure and ground motion anticipated at the construction site. It is believed that the availability of this design slip load spectrum will lead to a greater acceptance by the engineering profession of this new and innovative structural concept. / Applied Science, Faculty of / Civil Engineering, Department of / Graduate
|
14 |
A new hybrid method for three-dimensional dynamic soil-structure interaction.Mathur, Ravindra Prasad. January 1989 (has links)
A hybrid method based on three-dimensional finite element idealization in the near field and a semi-analytic scheme using the principles of wave propagation in multilayered half space in the far field is proposed for dynamic soil-structure interaction analysis. It combines the advantages of both the numerical and analytical techniques. A structure resting on the surface or embedded in a multilayered soil-medium and subjected to vertically propagating plane waves is analyzed by using the method. An important aspect of the soil-structure interaction problem considered is the presence of waves scattered from the soil-structure interface and geometrical irregularities in the soil. The dynamic response of an embedded structure of rectangular cross section to a vertically propagating compressional pulse is solved as an example problem. The proposed method is verified by comparison of its predictions with those from a finite element procedure with absorbing boundaries, and from an analytical solution. The results from the hybrid method compare well with those from the other two, with closer correlation between the hybrid and analytical methods.
|
15 |
Computational assessment of seismic resistance of RC framed buildings with masonry infillLoots, Jurie 12 1900 (has links)
Thesis (MScIng)--Stellenbosch University, 2005. / Some digitised pages may appear illegible due to the condition of the original hard copy. / ENGLISH ABSTRACT: Reinforced concrete (RC) frames with unreinforced masonry infill form the structural system
of many buildings and this is also true for South Africa. It is common practice to consider the
masonry infill as a non-structural component and therefore it does not contribute to the
performance of the Re frame buildings under lateral loading such as earthquake loading.
This is done by leaving a sufficient gap between the Re frame and the infill. This ensures
that there is no contact between the frame and the infill during an earthquake event.
However, it has been suggested that masonry infill can play a significant role in the
performance of a Re frame building under lateral loading.
The first part of the study focuses on the South African situation. The relevance of shear
walls in these Re frame buildings as well as the size of the gap (between frame and infill) left
in practice, are investigated. This is done by finite element analysis.
The second part of the study focuses on the effects that the infill can have on the global
performance of the structure when there is full contact between the Re frames and infill. The
effect of openings in the infill to the response of the frame is also investigated. Finite element
models of single span Re frames with infill is built and analyzed in order to investigate
possible damage to the infill, frame infill interaction and to obtain the non linear stiffness of
the frame with infill as a whole. This obtained non linear stiffness can be modelled in Diana
as a non linear spring that will be used in the development of a simplified analysis method.
The simplified method developed consists of a frame and two such non linear springs, placed
diagonally, and which have the same force versus displacement behaviour as the original
frame with infill. These single span frames can be added together to model a whole frame. In
a first step to generalise the simplified method, various geometries of infills are considered,
varying span and height, as well as opening percentage, representing windows and doors of
varying total area and positioning. However, in this study a single masonry type, namely solid
baked clay bricks set in a general mortar, is considered. To generalise the approach further,
other masonry types can be considered in the same way. The use of these springs in a
simplified model saves computational time and this means that larger structures can be
modelled in Diana to investigate response of'Rf' frame buildings with infill. The work reported in this thesis considers only in-plane action. Out-of-plane-action of the
masonry infill has been reported in the literature to be considerable, under the condition that it
is sufficiently tied to the frame to prevent mere toppling over, causing life risking hazards in
earthquake events. This matter should be studied in continuation of the current research to
generalise the simple approach to three dimensions. / AFRIKAANSE OPSOMMING: Gewapende betonrame (GBR-e) met ongewapende messelwerk invulpanele (invul) vorm die
strukturele ruggraat van vele geboue en dit geld ook vir geboue in Suid-Afrika. Dit is
algemene praktyk om die invulpaneel in sulke geboue as 'n nie-strukturele komponent te
beskou. Daarvolgens dra dit nie by tot die gedrag van 'n GBR gebou onderhewig aan 'n
aarbewing nie. Dit word bereik deur 'n groot genoeg gaping tussen die betonraam en die
invul te los. Die gevolg is dat daar geen kontak tussen die betonraam en die invul plaasvind
indien daar 'n aardbewing sou voorkom nie. Dit is egter voorgestel dat invul 'n
noemenswaardige rol kan speel in die gedrag van 'n GBR gebou onderwerp aan 'n horisontale
las.
Die eerste deel van die studie fokus op die Suid-Afrikaanse situasie. Die relavansie van
skuifmure in GBR geboue asook die grootte van die gaping (tussen die raam en invul) wat in
die praktyk gebruik word, word ondersoek. Dit word gedoen met behulp van eindige element
analises.
Die tweede deel van die studie fokus op die effek wat invul kan hê op die globale gedrag van
'n struktuur wanneer daar volle kontak tussen die GBR en die invul is. Die effek wat die
teenwoordigheid van openinge in die invul kan hê op die gedrag van 'n GBR is ook
ondersoek. Eindige element modelle van enkelspan GBR met invul is gemodelleer en
geanaliseer om die moontlike skade aan die invul, die interaksie tussen die GBR en die invul
asook die nie-lineêre styfheid van die raam en invul as 'n geheel, te ondersoek. Hierdie nielineêre
styfheid kan in Diana as 'n nie-lineêre veer gemodelleer word en word gebruik in die
ontwikkeling van 'n vereenvoudigde metode.
Hierdie vereenvoudigde metode wat ontwikkel is, bestaan uit 'n raam en twee sulke nielineêre
vere (diagonaal geplaas). Die raam met vere het dieselfde krag teenoor
verplasingsgedrag as die van die oorspronklike raam met invul wat dit voorstel. Hierdie rame
kan saamgevoeg word om 'n raam uit 'n gebou as 'n geheel te modelleer. Verskeie invul
geometrieë word gebruik in die analises in 'n eerste stap om die vereenvoudigde metode te
veralgemeen. Die span en hoogte asook opening persentasie van die invul word gevariëer om
vensters en deure van veskeie grootte en posisie voor te stel. In die studie, 'n enkel
messelwerk tipe, naamlik solied klei bakstene geset in algemene mortar, word gebruik. Ander messelwerk tipes kan gebruik word om die metode verder te veralgemeen. Die gebruik van
die vere in die vereenvoudigde metode spaar berekenings tyd en dit beteken dat groter
strukture in Diana gemodelleer kan word om die gedrag van GBR geboue met invul te
ondersoek.
Die werk gedoen in die tesis neem slegs in-vlak aksie in ag. Literatuurstudie dui daarop dat
goeie uit-vlak-aksie van messelwerk invul bestaan, mits dit goed geanker is aan die raam om
te verseker dat dit nie kan omval en 'n gevaar vir lewens in 'n aardbewing inhou nie. Dit
behoort verder bestudeer te vord in die vervolging van die huidige ondersoek om die
vereenvoudige metode na drie dimensies te veralgemeen.
|
16 |
Seismic assessment of buildings in Hong Kong with special emphasis on displacement-based approachesSheikh, MD. Neaz. January 2005 (has links)
published_or_final_version / abstract / Civil Engineering / Doctoral / Doctor of Philosophy
|
17 |
Indeterminate reinforced concrete frames subjected to inelastic cyclic deformation.Samman, Tamim Abdulhadi. January 1987 (has links)
Four full-size statically indeterminate reinforced concrete frames with two symmetrical bays were tested to obtain sufficient data to evaluate the adequacy of the current ACI-ASCE Committee 352 design recommendations, as well as to determine whether a relaxation of some of the limits in these guidelines can be justified. Each specimen contained three 8.5-foot-long columns, connected at mid-height by two 9-foot-long beams. Initially, a constant axial load was applied to each column. The specimens were then subjected to a displacement-controlled loading schedule to simulate the type of displacements a frame may experience during a severe earthquake. In designing the specimens, the latest recommendations of the ACI-ASCE Committee 352 and the ACI building code ACI 318-83 were satisfied except for the following modifications: (1) the flexural strength ratio (M(R)) in the second specimen was reduced from 1.4 to 1.2, (2) the shear-stress factors (γ) in the joints of the third specimen were increased from 12 and 15 to 15 and 20 for the exterior and interior joints respectively, and (3) the number of the transverse reinforcements inside the right exterior joint in the fourth specimen was reduced from 4 to 2 sets of hoops. The conclusion inferred from the results indicate that for drift levels within the elastic range, the elongations and the rotations of the beam regions near the faces of the columns, in addition to the joint shear strains, were not affected by the design values for the primary variables in the last three specimens. For larger excursions into the inelastic range, the relaxation of the current Committee 352 design recommendations in the last three specimens not only showed a significant effect in reducing the elongations and the rotations of the beams, or in increasing the joint shear strains but led to lower energy dissipation of the specimens. Consequently, the current design guidelines by the ACI-ASCE Committee 352 yield statically indeterminate frames which exhibit sufficient ductility.
|
18 |
PERFORMANCE CRITERIA FOR REINFORCED CONCRETE BEAM-COLUMN CONNECTIONS.Yacoub, Mohamad Toufic, 1957- January 1986 (has links)
No description available.
|
19 |
DYNAMIC SOIL-STRUCTURE INTERACTION IN A LAYERED MEDIUMRomanel, Celso, 1952- January 1987 (has links)
The most popular method in dynamic soil-structure interaction analysis is the finite element method. The versatility in problems involving different materials and complex geometries is its main advantage, yet FEM can not simulate unbounded domains completely. A hybrid method is proposed in this research, which models the near field (structure and surrounding soil) by finite elements and the far field by a continuum approach. The system is excited by monochromatic body waves (P and SV) propagating with oblique incidence and harmonic time dependence. The far field problem is solved using Thomson-Haskell formulation associated with the delta matrix technique. The soil profile does not contain any soft layer and the layers are assumed to be linearly elastic, isotropic, homogeneous and perfectly bonded at the interfaces. Two-dimensional (in-plane) formulation is considered and the analysis is performed on both k- and o-planes through time and spatial Fourier transforms of the field equations and boundary conditions. (Abstract shortened with permission of author.)
|
20 |
Response of rock tunnels to earthquake shaking.Rozen, Arnon January 1977 (has links)
Thesis. 1977. M.S.--Massachusetts Institute of Technology. Dept. of Civil Engineering. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Includes bibliographies. / M.S.
|
Page generated in 0.1161 seconds