Precast Concrete Retaining Walls

Introduction

The unit has a plain concrete finish as struck from the mould. 4No. 30mm dia holes are formed through the base for anchorage. Additional holes are provided through the stem for lifting the various heights of unit.

Design Criteria

Designed in accordance with B.S.8110 Part 1 1985. Concrete grade 45/20 O.P.C. Manufactured using Portland Cement to B.S.12 and aggregates to B.S.882. Bulk density of retained material 18kN/m³ (approx 1800 kg/m³). The units are designed to retain material on either or both sides. The design assumes that the material is adequately drained. If required weepholes can be formed during casting. It is usual to allow a 10mm joint as tolerance between units to absorb creep.

Foundations

The foundation requirements should be determined by a qualified engineer. Units placed on a concrete foundation should be bedded on mortar and wedged to attain correct alignment. Where it is necessary to anchor the unit to the foundation see “Stability”.

Stability / Anchors for Standard Conditions

Anchors comprise of 4No. T20 high yield deformed bars with nominal penetration of 150mm both into the foundation and the unit, used with a two part resin mortar* in accordance with the manufacturer’s instructions. Position the tee walls onto the concrete foundation and align using a cement mortar bed and shims as required. With the 30mm diameter holes in the unit base as a guide, drill into the foundation to the required depth using a 28mm diameter rotary percussive drill to give rough sided holes (do not use a diamond drill which leaves a smooth sided hole). Pour sufficient mixed resin into the hole first then insert the T.20 bar to the full depth so that the resin covers and encapsulates the bar. *as for Retaining Walls

Important Points to Remember

● Drill sufficient holes ahead to allow the use of a complete container of mixed resin.
● The mortar is placed in the hole first.
● Follow the resin manufacturer’s instructions for placing the anchor bars in the resin.
● Anchors are to prevent sliding and are the suggested method for location on concrete surfaces.
● Alternative methods may be used that give the equivalent resistance.