Showing papers on "Settlement (structural) published in 1971"

Performance of Four Foundations on End Bearing Piles

Abstract: The performance of four buildings each supported on end bearing concrete-filled pipe piles is evaluated. The piles were driven through a deep deposit of soft clay and are end-bearing in stiff glacial till and weathered shale. The paper presents measurements of building settlement, pile tip settlement of both test piles and foundation piles, pore pressures induced by the pile driving, and movements of adjacent buildings on shallow foundations caused by pile driving. The pile-supported buildings settled less than 0.5 in. The main conclusions from the study are: (1) The pile design load is controlled by tip punching considerations, because the settlement of the pile tip is small until the tip-bearing capacity is approached; (2) preaugering is effective in reducing pore pressures induced by the pile driving; and (3) even with preaugering, pile driving in soft clay can cause significant movement of adjacent buildings at distances up to 50 ft.

The development and testing of an impact roller

Abstract: THIS PAPER CONCERNS THE PERFORMANCE OF A 24,000 LB PENTAGON SHAPED PROTOTYPE COMPACTOR. THIS MACHINE IMPARTS A SERIES OF IMPACTS DUE TO ITS MASS DROPPING ABOUT 8 IN. ONTO AN AREA OF ABOUT 8 SQUARE FEET. STEADY ROLLING ACTION IS ACHIEVED BY SPRINGS AND DAMPING DEVICES IN THE TOWING MECHANISM. AT A RECENT TRIAL, SURFACE SETTLEMENT, SUB-SURFACE SETTLEMENT, PENETROMETER, AND DENSITY OBSERVATIONS, TOGETHER WITH PRESSURE CELL MEASUREMENTS, SHOWED THAT THE PENTAGON COMPACTOR ACHIEVED AN APPRECIABLY BETTER EFFECT THAN OTHER ROLLERS AND, WITH A HIGHER WORK OUTPUT, SHOULD PROVE TO BE ECONOMICAL. IT IS SUGGESTED THAT THE PENTAGON COMPACTOR OFFERS AN ALTERNATIVE TO HEAVY PNEUMATIC ROLLERS FOR PROOF OF SUBGRADES AND SHOULD PROVE USEFUL FOR COMPACTION OF MIXED SOIL AND ROCKS AND LANDFILL RUBBISH DUMPS AS WELL AS FOR DEEP COMPACTION SOILS IN GENERAL. /AUTHOR/

Settlement and load distribution analysis of pile groups

Abstract: Analyses are made of the settlement interaction between two compressible floating piles in a semi infinite mass, and between two compressible piles resting on a rigid bearing stratum. The results of these analyses are expressed in terms of interaction factors relating the increase in settlement due to the second pile to the settlement of a single pile. It is shown that, as previously found with incompressible floating pile groups, the interaction factors for two piles may be superposed to analyse the settlement and load distribution within any compressible pile group. The influence on group behaviour of the compressibility of the piles relative to the soil is examined for square groups of piles. It is found that, for a floating pile group, the settlement interaction decreases as the piles become relatively less compressible, and for a group with a rigid pile cap, the load distribution within the group becomes more uniform. In contrast, for a group of end bearing piles, the settlement interaction increases as the piles become relatively less compressible while the load distribution within a group having a rigid cap becomes less uniform. Comparisons between theoretical group behaviour and that observed from model and field tests generally show good agreement (a).

Settlements of two multistory buildings in Edmonton

Abstract: Settlement observations have been taken over a period of about 6 years for two multistory buildings on a clay till. The CN Tower is founded on spread footings and the Avord Armson on Franki expanded base concrete piles; both buildings have settled a maximum of about 3 cm (). The settlement measurements showed a rapid response to loading during the construction period. Analysis of the foundations by elastic theory is shown to account satisfactorily for the overall settlement pattern during the construction period. The modulus of elasticity derived from the observations is stress dependent, decreasing with increasing load intensity. A small amount of long-term settlement has occurred at the end of construction; after 6 years it is less than about 20% of the total. Predictions of settlement using parameters obtained from soil samples taken at the sites are unrealistically high when compared with measured settlements.

Submarine Pipeline Support By Marine Sediments

Abstract: An approximate method for determining the initial settlement of a submarine pipeline in cohesive marine soils was derived by use of analogy to theories developed for use with foundations on land. Equations and a graph provide upper and lower limits of the probable range of initial settlement in terms of the submerged weight of a unit length of the pipeline, soil cohesion, and the external pipe diameter. The limitations of soil sampling, the variability of soil cohesion along the route of a pipeline, and the need for experimental and field work on the determination of submarine pipeline settlement are discussed.

Embankments constructed on soft foundations: settlement study of avonmouth

Abstract: THE SETTLEMENT AND STABILITY OF A TRIAL EMBANKMENT CONSTRUCTED ON THE ROUTE OF THE BIRMINGHAM-EXETER (M5) MOTORWAY NEAR AVONMOUTH WERE INVESTIGATED. THE EMBANKMENT, WHICH WAS SQUARE IN PLAN, HAD A MAXIMUM HEIGHT OF 9.2M, A WIDTH AT THE BASE OF 67M AND SIDE SLOPES OF 1 IN 2 (27 DEGREES). IT WAS CONSTRUCTED OF PULVERIZED-FUEL ASH ON HIGHLY COMPRESSIBLE ALLUVIUM EXTENDING TO ABOUT 13 M DEPTH. MEASUREMENTS OF POREWATER PRESSURE, IN-SITU PERMEABILITY AND SETTLEMENT WERE MADE IN THE SUBSOIL TO ENABLE THE PERFORMANCE OF THE EMBANKMENT TO BE ASSESSED. THE INVESTIGATION HAS SHOWN THAT THE USE OF THE CONVENTIONAL THEORY OF CONSOLIDATION TOGETHER WITH THE SOIL PARAMETERS FROM LABORATORY TESTS PRODUCED VERY SIGNIFICANT UNDERESTIMATES OF THE RATE OF SETTLEMENT. A MORE SATISFACTORY SETTLEMENT PREDICTION WAS OBTAINED USING THE RESULTS OF IN-SITU PERMEABILITY TESTS TOGETHER WITH A SETTLEMENT ANALYSIS WHICH INVOLVED MORE REALISTIC ASSUMPTIONS. DURING CONSTRUCTION THE MINIMUM FACTOR OF SAFETY AGAINST SHEAR FAILURE WAS ESTIMATED TO BE ABOUT 1.7, THIS VALUE OCCURRING WHEN THE EMBANKMENT ATTAINED ITS FULL HEIGHT. AS THE MOST ADVERSE SUBSOIL CONDITIONS WERE ENCOUNTERED IN THE TRIAL AREA IT WAS, THEREFORE, DEMONSTRATED THAT STABLE EMBANKMENTS COULD BE CONSTRUCTED TO SIMILAR HEIGHTS AT OTHER LOCATIONS ON THE ALLUVIAL PLAIN. /TRRL/

Behaviour of piles

Abstract: THE STATE OF THE ART IS DESCRIBED FOR PILE DRIVING AND LOAD DISPLACEMENT CHARACTERISTICS OF PILES IN DIFFERENT SOILS. THE SETTLEMENT OF STRUCTURES, INSTALLATION PROCEDURES AND EFFECTS, AND INSTALLATION PROBLEMS ARE INCLUDED. /TRRL/

Analysis of uncertainty in settlement prediction

Abstract: A METHOD IS PRESENTED TO ANALYZE THE UNCERTAINTY ASSOCIATED WITH THE SETTLEMENT PREDICTION DETERMINED BY USE OF THE CONVENTIONAL DETERMINISTIC APPROACH. PROBABILITY DISTRIBUTION FUNCTIONS, INSTEAD OF INDIVIDUAL VALUES, ARE USED FOR THE VARIABLES IN THE FORMULA TO OBTAIN A PROBABILITY DISTRIBUTION FUNCTION FOR THE SETTLEMENT DUE TO PRIMARY CONSOLIDATION. THE DISTRIBUTIONS FOR SOIL PROPERTIES ARE ESTABLISHED FROM A STATISTICAL TREATMENT OF TEST RESULTS, WHILE THOSE FOR THE STRESS PARAMETERS ARE DEDUCED ON A MORE SUBJECTIVE BASIS. THE STUDY IS GENERALIZED BY REPEATING THE PROCESS FOR A LARGE NUMBER OF CASES. VALUES CALCULATED THERE FROM ARE THEN USED IN REGRESSION ANALYSES TO DEVELOP EMPIRICAL EQUATIONS WHICH PROVIDE A MEASURE OF THE UNCERTAINTY ASSOCIATED WITH A WIDE RANGE OF INPUT PARAMETERS FOR THIS PARTICULAR PROBLEM. FINALLY, THESE EQUATIONS ARE REPRESENTED IN THE FORM OF NOMOGRAPHS WHICH FACILITATE THEIR USAGE. /AUTHOR/

Displacements in a soil mass due to pile groups

Abstract: THE SETTLEMENT OF COMPRESSIBLE SOIL LAYERS UNDERLYING PILES AND THE SETTLEMENT OF THE GROUND SURFACE SOME DISTANCE AWAY FROM PILES, E.G. THE ADDITIONAL SETTLEMENT OF AN EXISTING BUILDING DUE TO A NEW STRUCTURE, ARE EXAMINED. NUMERICAL SOLUTIONS ARE OBTAINED FOR THE VERTICAL DISPLACEMENT WITHIN A SOIL MASS DUE TO A SINGLE LOADED PILE; USING THESE SOLUTIONS, THE AUTHORS DESCRIBE METHODS FOR CALCULATING THE SURFACE DISPLACEMENT PROFILE AROUND A PILE GROUP AND THE SETTLEMENT OF SOIL LAYERS BENEATH A PILE ON A PILE GROUP. IN OBTAINING THE SOLUTIONS FOR THE DISPLACEMENTS DUE TO A SINGLE PILE, IT IS ASSUMED THAT NO LOCAL FIELD OCCURS BETWEEN THE PILE AND THE SOIL, AND THAT CONDITIONS WITHIN THE SOIL REMAIN PURELY ELASTIC. IN CONSIDERING THE SETTLEMENT OF PILE GROUPS, THE GROUPS ARE ASSUMED TO BE FREE-STANDING WITH NO CONTACT BETWEEN THE PILE CAP AND THE SOIL. ANALYSIS HAS SHOWN THAT, EVEN IF THE PILE CAP IS, IN FACT, IN CONTACT WITH THE SOIL, IT HAS LITTLE INFLUENCE ON THE SETTLEMENT OF THE GROUP, PROVIDED THE PILE SPACING IS RELATIVELY CLOSE AND ELASTIC CONDITIONS PREVAIL WITHIN THE SOIL. /TRRL/

A probabilistic approach to estimating differential settlement of footings on sand.

Abstract: A PROBABILISTIC APPROACH TO ESTIMATING DIFFERENTIAL SETTLEMENT OF FOOTINGS ON SAND

Anchored diaphragm walls in sand-some design and construction considerations

Abstract: THE PAPER INTRODUCES A METHOD OF ESTIMATING THE ANCHOR LOADS REQUIRRED TO SUPPORT A MULTI-TIED CONTINUOUS WALL BY CALCULATING THE POSITION AND MAGNITUDE OF A RESULTANT TIE AT ANY STAGE OF EXCAVATION, THE WALL BEING TREATED AS A SINGLE-TIED STRUCTURE. COMPARISON OF DESIGNS CARRIED OUT BY THE CEMENTATION METHOD AND BY EXPERIMENTAL WORK INDICATES THAT THE RESULTS OBTAINED PROVIDE A GOOD ESTIMATE OF THE HORIZONTAL FORCES. ALSO SHOWN ARE THE RESULTS OBTAINED BY THE GENERALLY USED METHODS. THE NEW METHOD HAS THE ADVANTAGE OF BEING A REPETITIVE SINGLE-TIED WALL DESIGN, AND IT IS AMENDABLE TO VARYING SOIL STRATA WHICH HAS ALWAYS BEEN A PROBLEM WHEN IMPLEMENTING THE TRAPEZOIDAL METHOD. THE PAPER THEN DESCRIBES THE MAIN DESIGN AND STABILITY CONSIDERATIONS ASSOCIATED WITH TRENCH EXCAVATION UNDER BENTONITE, AND GIVES RECOMMENDATIONS COVERING THE MAIN REQUIREMENTS FOR TREMIE CONCRETE FOR LOAD BEARING DIAPHRAGM WALLS. METHODS OF ESTIMATING ANCHOR LOCATION, OVERALL STABILITY AND LOAD CARRYING CAPACITY WITH RELEVANT SAFETY FACTORS, ARE ILLUSTRATED. ANCHOR CONSTRUCTION STAGES ARE DESCRIBED TOGETHER WITH THE POST-TENSIONING AND CORROSION PROTECTION NORMALLY RECOMMENDED FOR SAND ANCHORS. FINALLY, THE INFLUENCE OF PRESTRESSED TIE- BACKS ON THE LATERAL MOVEMENTS AND SETTLEMENT OF THE RETAINED SOIL MASS IS DISCUSSED. /RRL/

Settlement of Embankment on Layer of Soil

Abstract: Practicing engineers are often concerned with the computation of the settlement of a layer of compressible soil bearing an embankment of great length with a symmetrical either triangular or trapezoidal cross section. This note attempts to establish tables and charts allowing these calculations to be done quickly.

The influence of oil and detergents on recolonization in the upper intertidal zone

Abstract: Re colonization of asbestos fouling plates treated variously with oil and detergents is dependent on the season of the year. The presence of oil favors C. fissus settlement but retards algal settlement.

Patterns of Settlement in the James River Basin, 1607-1642

Abstract: The purpose of this study is to trace the sites of set­ tlement as they developed along the James River from 160? to 1642? to describe their characteristics and growth patterns? and to illustrate their location and unique features through the use of maps. Old World theories of land and its utilization accom­ panied the first colonists to Virginia, but the expanse of virgin wilds and the harsh realities of America soon altered ' the settlers* preconceptions. The easy availability of land and its broad distribution by headright contributed to a fluid society where property was attainable for the masses and realty determined a person’s place in the social hier­ archy , Having secured a foothold Sit Jamestown, the Virginia Company, large private and investor-type plantations, and* after 1620, individual yeomen claimed lands and opened re­ gions for settlement along the James and its tributaries, up­ stream and down. This random and casual diffusion of popula­ tion was disrupted by the devastating Indian massacre of 1622, Many western, upriver settlements were ravaged and abandoned. Large numbers of refugees fled eastward to the strate­ gically located old centers at Jamestown and Elizabeth City. They and their contiguous suburbs were defensible clusters of population— communities in the true sense* influencing land patents and seatings for much of the period. Claims to new lands in the wake of the massacre re­ flected caution and conservatism even among large specula­ tors, with most activity restricted to established regions. Well into the 1630s the eastern, Chesapeake Bay-oriented communities and counties displayed the greatest growth• Above all, the colonists’ response to their new environment between 160? and 1642 was experimental, ad hoc, stalked by tragedy, and beset by error. PATTERNS OF SETTLEMENT IN THE JAMES RIVER BASIN, 160716^2

Discussion of "Static Cone to Compute Static Settlement over Sand"

Abstract: WITH REFERENCE TO SCHMERTMANN'S STUDY OF STRUCTURAL SETTLEMENT ON SAND, IN WHICH HE USED VERTICAL STRAIN DISTRIBUTION IN PLACE OF THE CLASSICAL METHOD TO PREDICT SETTLEMENT, THE WRITERS REPORT ON THEIR MEASUREMENTS OF STRUCTURAL SETTLEMENT ON DEEP DEPOSITS OF ALLUVIAL AND AEOLIAN SANDS, PARTICULARLY FOR THREE LARGE-DIAMETER OIL-STORAGE TANKS. DATA REPORTED TO DATA TEND TO CONFIRM THE AUTHOR'S VIEW THAT STRAIN DISTRIBUTION, WHICH IS CRITICAL IN SHALLOW SAND PROFILES, IS A FUNCTION OF SAND DENSITY AND COMPRESSIBILITY.

Discussion of performance of four foundations on end bearing piles

Abstract: THE AUTHORS HAVE PRESENTED A CONSIDERABLE AMOUNT OF INTERESTING SETTLEMENT AND PORE PRESSURE DATA FOR PILE FOUNDATIONS. THE PILE-GROUP SETTLEMENT DATA ARE PARTICULARLY INTERESTING BECAUSE OF THE OPPORTUNITY TO COMPARE THE MEASURED VALUES WITH VALUES PREDICTED THEORETICALLY. ANALYSES RELATING PILE-GROUP AND SINGLE-PILE SETTLEMENTS HAVE BEEN DESCRIBED BY POULOS FOR INCOMPRESSIBLE FRICTION AND END-BEARING GROUPS. IN THESE ANALYSES, THE GROUP-PILE AND SINLE-PILE SETTLEMENTS ARE RELATED BY SUPER POSITION OF INTERACTION FACTORS FOR TWO PILES: THE INTERACTION FACTOR, ALPHA, BEING THE INCREASE IN SETTLEMENT DUE TO THE SECOND PILE AS A FRACTION OF THE SINGLE PILE SETTLEMENT. FACTOR ALPHA IS A FUNCTION PRIMARILY OF THE LENGTH-TO-DIAMETER RATIO, THE PILE SPACING RELATIVE TO THE DIAMETER, AND THE COMPRESSIBILITY OF THE PILE RELATIVE TO THE SOIL, EXPRESSED AS THE PILE STIFFNESS FACTOR K, WHICH FOR A SOLID-PILE SECTION IS THE RATIO OF THE MODULUS OF THE PILE TO THAT OF THE SOIL. ALTHOUGH GROUPS IN RELATIVELY SQUARE ARRAYS HAVE BEEN CONSIDERED, THE EXACT CONFIGURATION OF THE PILE WITHIN THE GROUP HAS LITTLE EFFECT ON THE GROUP SETTLEMENT, ESPECIALLY FOR GROUPS CONTAINING LARGER NUMBERS OF PILES. THE COMPUTER RELATIONSHIP BETWEEN SETTLEMENT AND GROUP SIZE, TOGETHER WITH THE AUTHORS MEASURED VALUES, IS SHOWN IN FIG. 14. BECAUSE OF THE CONSIDERABLE SCATTER IN THE MEASURED VALUES, A LINEAR REGRESSION LINE HAS BEEN CALCULATED FOR THESE VALUES AND IS ALSO SHOWN IN FIG. 14. IT CAN BE SEEN THAT THE AGREEMENT BETWEEN THE COMPUTER AND MEASURED SETTLEMENTS IS SUFFICIENTLY GOOD TO SUGGEST THAT THE THEORETICAL ANALYSIS IS CAPABLE OF PROVIDING A REASONABLE MEANS OF PREDICTING GROUP SETTLEMENTS FROM A KNOWLEDGE OF THE SINGLE-PILE SETTLEMENT. /DISCUSSER/