## 2 Terminologies and Definitions of Integral Bridges  
The diversity in design and construction of integral bridges created various terminologies and definitions. The type of design and construction ultimately has ramifications on the geotechnical aspects of integral bridges. According to the widely accepted definition used by bridge engineers, an integral bridge is one where the bridge deck is without any expansion or contraction, and they can be sub-categorised as an integral abutment bridge (IAB) or a semi-integral abutment bridge (SIAB). A bridge with a fully continuous or integral connection between the deck and the abutment is defined as an IAB. In the literature, IABs are also referred to as fully integral abutment bridges (FIABs). The SIAB, like the IAB, has a continuous deck without joints, but with bearings between abutments and the bridge deck, such that the superstructure is not continuous or monolithic with the abutments. It is noted that the terms IAB and SIAB are quite extensively used in North America. The American Association of State Highway and Transport Officials (AASHTO) Load and Resistant Factor Design (LRFD) Bridge Design Specifications [23] offers a slightly different definition. According to AASHTO, an integral bridge is a bridge without deck joints having integral abutments that are rigidly attached to the superstructure and supported on a spread footing or pile foundation designed to resist and/or absorb creep, shrinkage,and thermal deformations of the bridge superstructure. This definition is analogous to that of an IAB as defined in the paragraph above. SIAB unfortunately does not fit into this definition. The AASHTO does not further sub-classify integral bridges, although most of the states in the USA have included design guidelines for different sub-classes of integral bridges in their design manuals. In European countries, integral bridges are commonly defined as either fully integral bridges or semi-integral bridges [24]. Integral bridges are defined based on the connection between the continuous deck and abutment. There are no expansion joints and bearings in fully integral bridges, and this is analogous to the definition adopted by others for IABs. In the same way, semi-integral bridges are analogous to the definition of SIABs. PD 6694-1 [25], published by the British Standards Institution (BSI), defines an integral bridge as a continuous bridge (continuous deck without any joints), which accommodates expansion and contraction of the bridge deck by the movement of the abutments in and out of the backfill. It also classifies the types of integral and semi-integral abutments for the integral construction of the integral bridges. PD 6694-1 categorises three types of abutments for integral construction: full height frame abutments as shown in Figure 1a-c, embedded wall abutment as shown in Figure 1d, and end screen abutments as shown in Figure 1e-i. The movements in full height frame abutments are accommodated by rotation or flexure of the abutment wall--whereas, in end screen abutments, the abutments can translate in and out of the fill to compensate for the deck movements. PD 6694-1 [25] provides further sub-classifications for end screen abutments: bank pad abutments including those supported on the ground or piles as shown in Figure 1e-g, flexible support abutments as shown in Figure 1h, and semi-integral abutments as shown in Figure 1i. According to PD 6694-1 [25], semi-integral abutments consist of the movement bearings at the connection between the vertical support at the end of the bridge deck and conventional or embedded walls or reinforced soil abutments. The movement bearing connection accommodates the deck expansion and contraction without transferring the effect to the bridge abutment. Figure 1: Cont. As it may be observed, the various definitions used in North American and European practice do not map entirely onto each other and may thus cause ambiguity in some cases.