8/9/2019 cem417wk2- -5

1/42

8/9/2019 cem417wk2- -5

2/42

TYPES OF WALLS

Mass retaining wallsCantilever walls

Counterfort retainingwallsPrecast concreteretaining walls

Precast concrete crib-retaining walls

8/9/2019 cem417wk2- -5

3/42

MASS RETAINING WALLSSometimes called gravity walls an d rely upontheir own mass together with the f riction on theunderside of the b ase to over come t he t endency t oslide o r ove rturnGenerally only economic up to 1.8 mMass walls can be constructed of semi-engineering quality b ricks bedded in a 1:3 cementmortar or of mass concreteNatural stone i s suitable for small walls up to 1mhigh but generally it is u sed as a facing materialfor w alls ov er 1 m

8/9/2019 cem417wk2- -5

4/42

TYPICAL EXAMPLE OF MASSRETAINING WALLS

BRICK MASS RETAINING WALL

8/9/2019 cem417wk2- -5

5/42

Brick retainingwall

Stone retaining wall

8/9/2019 cem417wk2- -5

6/42

TYPICAL EXAMPLE OF MASSRETAINING WALLS

MASS CONCRETE RETAINING WALL WITH

STONE FACINGS

8/9/2019 cem417wk2- -5

7/42

CANTILEVER WALLSUsually of reinforced concrete a nd work on theprinciple of leverage w here t he st em is d esigned as acantilever xed at the b ase an d the b ase i s d esigned asa cantilever xed at the st emEconomic height range of 1.2 m to 6 m using pre-stressing techniques

Any durable facing matesurface t o improve ap pearance of the wall

8/9/2019 cem417wk2- -5

8/42

Cantilever wall

8/9/2019 cem417wk2- -5

9/42

Two ba sic forms:- A base with a large heel A cantilever with a la

Cantilever LCantilever T

8/9/2019 cem417wk2- -5

10/42

8/9/2019 cem417wk2- -5

11/42

CANTILEVER WALLS

8/9/2019 cem417wk2- -5

12/42

8/9/2019 cem417wk2- -5

13/42

8/9/2019 cem417wk2- -5

14/42

COUNTERFORT RETAININGWALLS

Can be con structed of reinforced or p restressedconcreteSuitable for ov er 4 .5 m

Triangular beams placed at suitable centresbehind the s tem and above t he ba se t o en able t hestem and base t o ac t as slab spanninghorizontally over or u nder t he cou nterforts

8/9/2019 cem417wk2- -5

15/42

8/9/2019 cem417wk2- -5

16/42

8/9/2019 cem417wk2- -5

17/42

8/9/2019 cem417wk2- -5

18/42

PRECAST CONCRETERETAINING WALL

Manufactured from high-grade p re cast concrete on thecantilever p rinciple.Can be er ected on a foundation as p ermanent retaining wallor be f ree st anding to a ct as d ividing wall between heaped

materials w hich it can increase t hree t imes t he st oragevolume for any given areaOther advantages- reduction in time by eliminating curingperiod, cost of formwork, time t o erec t and dismantle t hetemporary forms

Lifting holes a re p rovided which can be u tilized for xing ifrequired

8/9/2019 cem417wk2- -5

19/42

APPLICATION

8/9/2019 cem417wk2- -5

20/42

8/9/2019 cem417wk2- -5

21/42

PRECAST CONCRETERETAINING WALLS

8/9/2019 cem417wk2- -5

22/42

PRE CAST CONCRETE CRIB-RETAINING WALLS

Designed on the p rinciple of mass retaining walls A system of pre

components comprising headers an d stretchers w hichinterlock to form a 3 dimensional framework or crib ofpre ca st concrete t imber u nits w ithin which soil isretainedConstructed with a face b atter between 1:6 and 1:8Subsoil drainage i s n ot required since t he op en faceprovides adequate drai nage.

8/9/2019 cem417wk2- -5

23/42

8/9/2019 cem417wk2- -5

24/42

SUBSOIL

DRAINAGE

8/9/2019 cem417wk2- -5

25/42

At the end of week this lecture, studentwill be able to :- Identify the functions of various

subsoil drainage system. C!"# C!$%

8/9/2019 cem417wk2- -5

26/42

8/9/2019 cem417wk2- -5

27/42

SOURCE OF WATER

8/9/2019 cem417wk2- -5

28/42

BUILDING REGULATION C2-RESISTANCE TO MOISTURE

'ubsoil drainage shall be )rovided if it is needed to avoid:-he )assage of ground moisture to the interior of the

buildingamage to the fabric of the building

/eeded for sites with a high water table level at whichwater occurs naturally below the ground%!b jective of subsoil drainage ( to lower the water table to alevel such that it will not rise to within 0.*1 m of the lowest

floor of a buildingAdvantages ( im)rove the stability of the ground, loweringthe humidity of the site and im)rove its horticultural

)ro)erties

8/9/2019 cem417wk2- -5

29/42

The water collected by a subsoil drainage syst emhas t o be con veyed to a suitable ou tfall such as ariver , lake or s urface w ater d rain and sewer.

8/9/2019 cem417wk2- -5

30/42

THE IDEAL SITE

8/9/2019 cem417wk2- -5

31/42

TYPICAL SUBSOIL DRAINAGEDETAILS

8/9/2019 cem417wk2- -5

32/42

MATERIALS OF SUBSOILDRAINAGEPorous - absorb water through their walls an d thus keepout ne particles o f soil or si ltPerforated Holes in pipe of different pattern whichallow water to en ter into t he p ipe a nd channels t o acollection points a nd discharged into t he d esignatedoutlet.

8/9/2019 cem417wk2- -5

33/42

8/9/2019 cem417wk2- -5

34/42

POLYETHYLENE PIPE

8/9/2019 cem417wk2- -5

35/42

PERFORATED PIPE

Perforated pipes for footing drains& ABS pipe for downspout drains

8/9/2019 cem417wk2- -5

36/42

Subsoil !"i#"$%

8/9/2019 cem417wk2- -5

37/42

SUBSOIL DRAINAGESYSTEMS

he layout of subsoils drains willde)end on whether it is necessary to

drain the whole site or if it is onlythe substructure of the buildingwhich needs to be )rotected

8/9/2019 cem417wk2- -5

38/42

MODEL OF SUBSOILDRAINAGE

8/9/2019 cem417wk2- -5

39/42

8/9/2019 cem417wk2- -5

40/42

HERRINGBONE DRAINAGE

8/9/2019 cem417wk2- -5

41/42

MOAT DRAINAGE

8/9/2019 cem417wk2- -5

42/42

RIVER

The syst em is terminated at a su itable ou tfall such as a ri ver, stream or surfacewater sewerIn cases, permission must be ob tained before di scharging a subsoil system