The pressure cxcrtcd by the stored material on rcctangular planform flexible walled silos is investigated during filling and discharge. Tests on a large scale steel model silo with a pyramidal hopper showed that the stress state of the stored material is significantly influenced by the wall flexibility and boundary conditions. The measured wall pressures were very different to pressures predicted by traditional theories and existing design codes. This is because traditional theories were developed for rigid walled circular silos and they ignore the effects of stored material/structure interaction. In this thesis the results of tests to measure the stress state throughout the contents of a flexible silo and pyramidal hopper are presenteda nd compared with measurementso f the structural response. The tests show that the redistribution of stresses within the stored material is cxtcnsive and is influenced by the corners in non-circular silos and horizontal and vertical stiffeners. As wall flexibility increases, the ereis increased freedom for stresses imposed by the stored material to redistribute and reduce the structural forces in the wall. The measured pressure in the corners of the model silo were up to nine times the pressure as the centre of the wall at the same level. The failure to incorporate the redistribution in to the model design led to a considerable over estimate of the wall stresses. Many existing measurements of pressures in the stored material in silos were weakened because of inaccurate instrumentation. In this study. considerable care was taken during the selection of pressure cells. Calibration and equilibrium checks to ensure the accuracy of measured data. Pressure was measured in four directions at forty eight positions in the model to determine the total stress state throughout the stored material. The results showed that wall pressures were influenced by five different arching phenomena. It is concludedt hat the cxisting theory is not accurate for pressure calculation in flexible non-circular silos. The use of a more accurate theory for the calculation of wall pressure can lead to extensive savings in the cost of the silo structure.

No description available.

No description available.

No description available.

There has been increased concern in recent years over the level and nature of the ground vibrations. The importance of such vibration has increased rapidly due to developments in construction in urban areas, where the effects of ground borne vibration on both humans and structures are considerable. Research has been undertaken to improve techniques used in the measurements, analyses and evaluation of ground vibrations caused by rail and road traffic, blasting and in particular those generated from pile driving activities. The amplitude of the vibration caused by the pile driving operation is a function of pile type, hammer type and the ground conditions. In order to investigate the effects of these three variables, a large number of visits were made to different sites which provided a range of different driving conditions. The main requirements in the analysis of the vibrations measured include vibration amplitude and their relevant frequency. The vibration amplitude is usually expressed in term of peak particle acceleration, velocity or displacement. In this work, the ground vibration is measured in terms of peak particle velocity using velocity transducers (geophone). In order to evaluate the true peak particle resultant velocity, the three components of the ground vibration are measured simultaneously by three orthogonally positioned sets of geophone. Recording the vibration data is achieved by employing a portable digital recorder which digitizes the analogue signals recieved from the transducers and stores the captured data on standard floppy disks for further analysis. The results are presented in tables and diagrams and detailed comments are given in the discussion of the recorded data. Some methods of analyses are reviewed and two new methods are proposed. These proposed methods include the application of the hemispherical projection technique in interpreting and displaying the three dimesional vibration information into a two dimensional plane. The other method analysed the attenuation of the ground vibration according to the arrival time of the generated waves from the pile toe and along the ground surface. It is suggested that when the arrival times of these two wave fronts coincide at one particular point, a highest vibration amplitude may be expected at that poinL The effect of ground vibration on building is investigated in large scale test in Aitwick where the dynamic strain of purpose built L-shape walls are recorded during driving steel sheet and H-pile at different stand-off from the walls using a winch-drop-hammer and a vibrodriver.

This thesis is in two parts which are related by the common theme of tension stiffening. Part I develops the concept of a stress-strain envelope to model the behaviour of the concrete in tension below the neutral axis of a reinforced concrete beam. This is substantiated by an analysis of the data from fourteen test beams. The envelope concept is then applied to the calculation of the moment-curvature relationships for these beams, which are also compared with the test results .Part II presents an experimental investigation of the longitudinal reinforcement strain distributions in reinforced concrete tension members. Test results for fourteen specimens having various cross-sections and reinforcement types are presented, with the reinforcement strains being measured by strain gauging the reinforcement internally. The comprehensive analysis of the test results includes specific design recommendations concerning bond stresses at working loads. Suggestions are made for further work.

On a hot summer day, high levels of solar radiation are incident on concrete bridge decks, causing non-linear variations in temperature through the depths of the structures. The changes in temperature lead to axial expansion and curvature of decks. In addition, self-equilibrating stresses arise from the non-linearity of the temperature profiles. In continuous structures, where axial expansion and curvature may be restrained, secondary thermal stresses are induced also. Tests are described in which reinforced concrete beams were subjected to daily cycles of heating. Applied temperature profiles were similar to maximum positive profiles for the United Kingdom. It was found that a linear elastic analysis, based on the uncracked section, generally gave an adequate prediction of thermal strains of non-loaded and loaded single span beams during heating cycles. Changes in curvature, during heating, were substantially modified in the early stages of loading, due to the existence of creep curvatures. Two span beams were tested also, with special regard to changes in support reactions during heating. No evidence was found in any of the tests of increases in the extent of cracking as a result of heating. Daily heating cycles were imposed over several weeks and evidence was found of a steady increase in the coefficient of thermal expansion, attributed to drying. Changes in curvature resulting from non-uniform shrinkage were observed, these being greatest in non-heated beams. Creep curvatures were found to increase roughly in proportion to the time-averaged beam temperature. Creep results were compared with prediction methods, including an incremental rate of creep analysis. Additional tests are described in which variations in moisture content and in the coefficient of thermal expansion within members were identified, using a segmentation technique.

No description available.

No description available.

A review of the development of the analysis of frames with semi-rigid end restraint is given, including the treatment of frame stability and effective lengths. The available experimental data relating to the moment versus in-plane rotational behaviour of practical beam- to-column connections, as used in steel frames, has also been reviewed. This data is found to be a non- linear function of connection deformation. Methods of mathematically modelling connection data have been reviewed and an improved representation based on the use of cubic B-spline curve fitting techniques is proposed. An analytical procedure has been developed to investigate the influence of realistic end restraint on the strength and behaviour of "real" steel columns. A FORTRAN finite element computer program, which includes the effects of initial out-of-straightness, spread of yield and internal residual stresses is outlined. This is based on an incremental approach, with Newton Raphson equilibrium iterations, to follow the load-deflection behaviour up to the maximum load level. The validity of the procedure is verified by comparison with available experimental data for an end restrained column test. A parametric study was carried out to assess the behaviour of columns with semi-rigid end restraint. The important pararReters relating to the connection, the column section and the geometrical imperfections were studied. It was found that an increase in connection stiffness produces a corresponding reduction in column deflections and an increase in maximum load capacity, except in those cases where the column is so stocky that it can attain its full squash load. Effective length factors calculated from these results indicate the column design economies th at would be possible if the actual end restraint conditions were properly accounted for.