Pad Footings Research Articles

K-1005 フレッティング疲労強度に及ぼすパッド脚高さの影響(J04-2 フレッティング摩耗と疲労(2))(J04 フレッティング摩耗と疲労)

K-1005 フレッティング疲労強度に及ぼすパッド脚高さの影響(J04-2 フレッティング摩耗と疲労(2))(J04 フレッティング摩耗と疲労)

Performance of Foyle Bridge east abutment

The use of high quality granular embankment fill at Foyle Bridge enabled the east abutment to be founded directly on pad footings within the 13 m high approach embankment. This has allowed considerable savings to be made when compared with the piled foundation design proposed at tender. This foundation solution was possible because the free-draining sandy ground conditions ensured that embankment consolidation settlement was completed soon after the fill was placed. Also the bridge foundation differential settlement tolerances were relaxed to 40 mm and contingency plans were developed to shim the bridge-bearings to enable the designers to contend with the most unfavourable estimates of long-term settlement. The Paper describes the application of the observational method from the design stage, during which settlement predictions were made and contingency plans developed, to the post-construction stage, when settlement monitoring was carried out and contingency plans were reviewed. L'emploi d'un matériau de remblaiement granulaire de grande qualité a permis de fonder directement la culée du pont de Foyle sur des semelles installées dans le remblai de 13 m de haut. Ceci a permis de faire des économies importantes par rapport au projet initial de fondation sur pieux. Cette solution a pu être mise en oeuvre du fait du terrain sableux très drainant assurant au remblai un tassement de consolidation instantané. De plus, des tassements différentiels acceptables de plus de 40 mm sur les fondations du pont, combinés à un dispositif de relevage des éléments d'appuis ont permis aux concepteurs de faire face aux tassements résiduels probables les plus défavorables. L'article décrit les applications de la méthode d'observation depuis la conception durant laquelle les prévisions de tassements furent faîtes et les dispositifs d'adaptation éventuelle furent élaborés jusqu' à la construction lorsque les tassements ont été enregistrés et le dispositif de réglage revu.

Rotational stiffness of shallow footings

The details of footing design, the soil stiffness and the soil resistance all affect the rotation characteristics of column bases of structural frames. This can have a considerable influence on structural economics (strength design), structural deflections (serviceability design) and on structural stability. Of particular and increasing importance in structural design is the ability to predict structural deformations under serviceability load level conditions. However, only limited theoretical and experimental attention has been given to understanding the footing-soil interface behaviour of shallow footings for realistic foundation conditions. In this paper, a set of experimental results for shallow footing behaviour under load reversal is presented. Based on this work and on previous modelling attempts, a relatively simple theoretical model for predicting rotation behaviour of simple pad footings under the first loading condition is described.

Geotechnical input to major bridge project : Williams, D J J Geotech engng div ASCEV115, N3, March 1989, P322–339

The Gateway Bridge in Brisbane, Australia, is a major structure by world standards. It crosses the Brisbane River to form a link in an easterly bypass of the city of Brisbane. The total length of the structure is 1,527 m, comprising approach spans of precast two-cell prestressed concrete box girders, and a single-cell prestressed concrete cast-in-place box girder central span and cantilevers. The 260-m long central span is the longest of its type in the world. Considerable and varied geotechnical input was required for the design and construction of the bridge. The foundation conditions encountered varied locally and were highly variable along the length of the project. Foundation design changes were necessary during the course of construction and quite different foundation systems were employed along the length of the structure. These ranged from shallow pad footings on rock to deep-rock socketed piles. Approach embankment settlement problems were also encountered. Of most significance was the design of the rock socketed piles, used for the first time in the Brisbane area

Geotechnical Input to Major Bridge Project

The Gateway Bridge in Brisbane, Australia, is a major structure by world standards. It crosses the Brisbane River to form a link in an easterly bypass of the city of Brisbane. The total length of the structure is 1,527 m, comprising approach spans of precast two-cell prestressed concrete box girders, and a single-cell prestressed concrete cast-in-place box girder central span and cantilevers. The 260-m long central span is the longest of its type in the world. Considerable and varied geotechnical input was required for the design and construction of the bridge. The foundation conditions encountered varied locally and were highly variable along the length of the project. Foundation design changes were necessary during the course of construction and quite different foundation systems were employed along the length of the structure. These ranged from shallow pad footings on rock to deep-rock socketed piles. Approach embankment settlement problems were also encountered. Of most significance was the design of the rock socketed piles, used for the first time in the Brisbane area.

Settlement monitoring of buildings in Central Scotland

A programme of monitoring of buildings for settlement and cracking is described. Six sites in Central Scotland were chosen with work starting in 1973. The five types of construction involved in the study were three-storey reinforced concrete frames on cellular rafts founded on soft clay; four-storey reinforced concrete frame on strip and pad footings founded on mixed ground; five-storey reinforced concrete frame on raft founded on stiff clay; three-storey brick/blockwork building on cellular raft founded on soft clay and two-storey brick/blockwork buildings on rafts founded on very soft clay. Varying degrees of settlement and damage were observed. At only one site (Grangemouth) was the damage considered to be moderate. The buildings with cellular raft foundations performed well but solid rafts were found to be less effective in some cases. The results show good correlation with previously proposed means of defining threshold of damage due to differential settlement. L'article décrit un programme pour contrôler les bâtiments en ce qui concerne le tassement et la fissuration. Six emplacements ont été choisis en Ecosse Centrale, où le travail a commencé en 1973. Les cinq types de construction étudiées étaient des montures en béton armé à 3 étages sur des radiers cellulaires fondés sur de l'argile tendre; des montures en béton armé à 2 étages sur empattement à tampon fondé sur du terrain mixte; des montures en béton armé à 5 étages sur des radiers cellulaires fondés sur de l'argile rigide; des bâtiments en briques/blocs à 3 étages sur des radiers cellulaires fondés sur de l'argile tendre, et des bâtiments en briques/blocs à 2 étages sur des radiers fondés sur de l'argile très tendre. De différents degrés de tassement et de dégâts ont été observés. Les dégâts ont été évalués comme modérés à un emplacement seulement (Grangemouth). Les bâtiments sur les fondations avec les radiers cellulaires ont montré de bonnes performances, tandis que les radiers massifs se sont comportés de façon moins effective dans de certains cas. Les résultats indiquent une bonne corrélation avec les méthodes déjà proposées pour définir le seuil des dégâts dus au tassement différentiel.