Ultimate Lateral Load Research Articles

Laboratory Investigation on Caissons-Deformations and Vertical Load Distributions

A detailed laboratory investigation was undertaken to study the settlement and deflection behavior of open ended caissons on sandy soil. Effect of embedment depth, diameter, and point of lateral load application were studied due to combination of vertical and lateral loads. Results indicate that load shared by the skin friction is greater than the base resistance for higher embedment depth/diameter ratios. Hence, the long-term safety of the caissons depends on the unused part of the tip loads, as the skin friction is mobilized at low settlements. Load-settlement curves indicate that the soil behaves linearly elastic up to very small settlements and deflections (2 to 4% of diameter). For better comparison with numerical methods, elasto-plastic constitutive laws are a must. Observed results agree well with those available in the literature. It was found that neglecting the base resistance is uneconomical for caissons with predominantly vertical loads, but it is recommended in estimating ultimate lateral load capacity. These results also indicate that small scale laboratory tests conducted in controlled conditions allow rapid and reliable information on field performance of caissons.

Evaluation of Storm Loadings on and Capacities of Offshore Platforms

Currently, there are approximately 3,000 major platforms offshore the United States and an equal number of platforms offshore other countries around the world. Approximately one-third of these platforms have exceeded their design lives and are now being called on for extended service. Reassessment and requalification of this massive infrastructure has required development of new engineering procedures. This paper summarizes development of a simplified procedure to evaluate storm loadings imposed on offshore platforms and to evaluate the ultimate limit state lateral loading capacities of such platforms. Verification of these procedures has been accomplished by comparing results from the simplified analyses with results from three-dimensional, linear, and nonlinear analyses of a variety of template-type platforms. Several of these platforms failed, were near failure, or survived loadings from severe hurricanes. The simplified procedure is able to replicate the loadings and capacities indicated by the comple...

ULSLEA: A Limit Equilibrium Procedure to Determine the Ultimate Limit State Loading Capacities of Template-Type Platforms

AbstractDuring the past three decades, an immense amount of effort has been devoted to development of sophisticated computer programs to enable the assessment of storm wind, wave, and current loadings and the ultimate limit state capacity characteristics of conventional, pile-supported, template-type offshore platforms (Billington et al, 1993; Frieze, 1993; Hellan et al., 1993, 1994). These programs require high degrees of expertise to operate properly, are expensive to purchase and maintain, and require large amounts of manpower and time to complete the analyses. Due to the sophistication of these programs, experience has shown that it is easy to make mistakes that are difficult to detect and that can have significant influences on the results. This paper summarizes the second phase of development and verification of simplified procedures to evaluate environmental loadings and ultimate limit state lateral loading capacities of template-type platforms. Reasonable simplifications and high degrees of user friendliness have been employed in development of the software to reduce the engineering effort, expertise, and costs associated with the analyses. The computer program that has been developed to perform the simplified analyses has been identified as ULSLEA (ultimate limit state limit equilibrium analyses) (Mortazavi and Bea, 1994).

Static and dynamic analysis of timber shear walls

Light-frame wood structures have evolved in recent years to the point where their earthquake resistance is now questionable. Shear walls are commonly used to provide lateral stiffness and strength in wood buildings. Therefore, accurate predictions of the seismic behaviour of timber shear walls are necessary in order to evaluate the safety of existing timber buildings and improve design practice. This paper develops and validates a simple structural analysis model to predict the behaviour of timber shear walls under lateral static loads and earthquake excitations. The model is restricted to two-dimensional shear walls with arbitrary geometry. The nonlinear load –slip characteristics of the fasteners are used in a displacement-based energy formulation to yield the static and dynamic equilibrium equations. The model is embedded in a shear wall analysis program (SWAP) developed for microcomputer applications. The predictions of the model are compared with full-scale racking and shake table tests. The ability of the model to accurately predict the lateral stiffness, the ultimate lateral load capacity, and the complete earthquake response of timber shear walls is clearly demonstrated. Key words: dynamics, earthquakes, seismic response, timber construction, walls, wood.

Ultimate lateral pile capacity in two-layer soil : University of Sdyney chool of Civil and Mining Engineering reportR503, Aug 1985, 25P

Expressions are derived for the ultimate lateral load capacity of a in a two-layer cohesive soil profile. Both free head and fixed head piles are considered, and, in each case, dimensionless solutions are given for failure of the supporting soil (short pile failure) and failure of the itself (long pile failure). Some parametric solutions are plotted, and an illustrative example is given to demonstrate the application of the analysis. (TRRL)

Ultimate lateral load on piles used to stabilize landslides : Viggiani, C Proc 10th International Conference on Soil Mechanics and Foundation Engineering, Stockholm, 15–19 June 1981V3, P555–560. Publ Rotterdam: A. A. Balkema, 1981

Ultimate lateral load on piles used to stabilize landslides : Viggiani, C Proc 10th International Conference on Soil Mechanics and Foundation Engineering, Stockholm, 15–19 June 1981V3, P555–560. Publ Rotterdam: A. A. Balkema, 1981

Probability Distributions for Wood Walls in Bending

Strength and stiffness distributions of wood‐stud walls were simulated on a computer using experimentally determined properties of framing, sheathing, and joints. Distributions were generated for conventional wall constructions framed with Douglas‐fir and southern pine studs of Stud grade, and sheathed with nominal 3/4 in. (19.0 mm) bevel siding of 3/8 in. (9.5 mm) plywood siding on one side and 1/2 in. (13 mm) gypsunv wallboard on the other side. This construction represents common types of walls with proven infield performance. Each simulated wall was analyzed by a computer model. The ultimate lateral load and average and maximum stud deflections were fitted to Weibull three parameter probability functions. The results, based on stud properties unadjusted for moisture content or load duration, indicate that all simulated wall types can sustain loads exceeding those expected in a 100 year wind. Actually, all wall types except those with 24 in. (610 mm) stud spacing would be safe under a 200 year wind in ...

Design of Rigid Shafts in Clay for Lateral Load

Using the results of eight field load tests reported in the literature, the ultimate lateral load for rigid shafts in clay is defined as the load corre sponding to a shaft rotation of 2 degrees. Th...

Outline of earthquake provisions in the recently revised Japanese building code

The revised building code of Japan, to become effective in June, 1981, is reviewed. It features a two-phase design for earthquakes. The first phase design is for medium earthquake motions, and this is basically the unchanged traditional seismic design. The new second phase design is intended to give protection to buildings in case of severe ground shaking. It requires the checking of several aspects of the building that has been proportioned by the first phase design. These include storey drift, vertical stiffness distribution, horizontal accentricity and ultimate lateral load carrying capacity. Both phases of the design are reviewed in detail, with some numerical examples where it is appropriate to illustrate the design procedure. Some provisions are discussed in the light of recent earthquake damage in Japan. A comparison with New Zealand seismic design loadings is also made.

Nailed wood joints under combined loading

A new testing apparatus was designed and a test method developed to enable the application of axial loads, lateral loads, and controlled ratios of axial to lateral loads to nailed wood joints. The effect of axial load components on ultimate lateral load, joint deformations and several slip moduli were evaluated. These load-slip parameters were determined for three species of wood, three depths of nail penetration, and eight angles of load application.

Lateral Load-Deflection Prediction for Pile Groups

A simple method of predicting the load-deflection behavior of a laterally loaded pile group is developed by combining a non linear load-deflection analysis for a single pile with an elastic analysis of pile groups. The parameters most influencing the prediction are the soil modulus and the ultimate lateral load of a pile in the group, Hu. The soil modulus may be backfigured from a lateral load test on a single pile and a method of interpretation of the test is described. The lateral load capacity of an isolated single pile also may be estimated and by multiplying this value by a lateral group efficiency factor, Hur may be determined. A number of comparisons between the observed and predicted load-deflection behavior of model pile groups, show good agreement and suggest that the proposed method is capable of providing satisfactory load-deflection predictions for laterally loaded pile groups, provided appropriate values of soil modulus and Hur can be input into the analysis.

Design of Steel Pile Foundations for Transmission owers

A method of designing steel piles for transmission towers using published theories for uplift and lateral loads is presented. Allowable horizontal deflection is not considered; however, with an adequate factor of safety applied to the ultimate lateral pile load, the horizontal deflection could be within tolerable limits for transmission tower foundations. Combined uplift and lateral load analysis indicate that the uplift resistance is increased by lateral loads. Although the lateral load of a battered pile is increased due to the batter, it is recommended that this increase be regarded as an additional safety factor for the commonly used batters.