GEOGUIDE 1 GUIDE TO RETAINING WALL ... - HKU Libraries

20durability of the wall during its design life and the maintenance requirements must beconsidered in the selection and specification of materials for construction and in theevaluation of design parameters. The local climate and environment under workingconditions should also be taken into account.Some guidance on how concrete, steel and timber can be expected to deteriorate indifferent circumstances is given in BS 8004 (BSI, 1986a), which also indicates some of thesteps which may be taken to prolong the life of these materials when used in foundations.2.6 AESTHETICSRetaining walls can be very dominant features on the urban and rural landscape.Careful design can make a considerable improvement to their appearance without leading toa significant increase in cost.Apart from having to satisfy the functional requirements, a retaining wall should, asfar as possible, be made to blend in with its surrounding environment and to be aestheticallypleasing. The aspects of a retaining wall that are important to its aesthetic impact are :(a) height of the wall and inclination of its front face,(b) curvature of the wall on plan (poor design can give theappearance of a 'kink' in the longitudinal elevation of thewall),(c) gradient and surface treatment of the adjacent ground,(d) surface textures of the front facing, and the expression andposition of vertical and horizontal construction joints, and(e) the coping of the wall.Aesthetic improvement can be achieved through the choice of. a suitable structuralform. Often, suitable types of vegetation can be incorporated to improve the appearance ofthe retaining wall. Guidance on the planting of grass, trees and shrubs in Hong Kong isgiven in the Geotechnical Manual for Slopes (GCO, 1984). Care should be taken to ensurethat the proposed planting will not cause any damage to the wall in the long term. Theappearance of a retaining wall may also be improved by providing features in the finishedface or decorative facings. The advice of a landscape architect should be sought wheneverappropriate.2.7 PATENTSCertain proprietary systems and components of retaining walls are covered by patents.Tender and contract documents should contain suitable clauses to ensure that no unforeseenliabilities are incurred by the employer with respect to the use of patented products.