Construction World December 2020

Category: CONSULTING ENGINEERS

COASTAL PARK: MATERIAL’S RECOVERY FACILITY CONSTRUCTION OF BULK EARTHWORKS PLATFORM OVER MUNICIPAL SOLID WASTE

Culture change and embracing a green economy starts with design and embracing that risk and change through design.

T he City of Cape Town understands this need, and that the recycling of everyday recyclable waste products will not only H[WHQG ODQGͤOO OLIH LQ WKH &LW\ EXW DOVR SURPRWH D FXOWXUH RI ZDVWH reduction and create an economy for the re-use of recyclable ZDVWH PDWHULDOV $ 0DWHULDOV 5HFRYHU\ )DFLOLW\ LV D VSHFLDOLVHG SODQW WKDW receives co-mingled recyclable waste, and through a combination of mechanical sorting and hand picking by labour, separates and prepares recyclable materials into dedicated streams for marketing to end-user manufacturers who use recycled products as raw PDWHULDOV LQ WKHLU PDQXIDFWXULQJ RU LQGXVWULDO SURFHVV 5HF\FODEOH ZDVWH LQ &DSH 7RZQ FDQ IRUP EHWZHHQ RI the waste stream by volume, and accounting for successful GLYHUVLRQ WR D 05) FDQ UHVXOW LQ D ODQGͤOO DLUVSDFH VDYLQJ RI FORVH WR WKH VDPH SHUFHQWDJH 1RW RQO\ GRHV WKLV H[WHQG WKH ODQGͤOO operating life, making waste disposal more economical, but also promotes sustainable re-use of recyclable waste products in the ZDVWH HFRQRP\ 7KH &RDVWDO 3DUN 05) ZLOO EH WKH &LW\̵V rd 05) IDFLOLW\ DIWHU .UDDLIRQWHLQ 05) DQG $WKORQH 05) ZHUH FRPSOHWHG LQ WKH V DQG WKH ͤUVW WR EH VLWHG RQ DQ H[LVWLQJ RSHUDWLRQDO ODQGͤOO VLWH ZKHUH ZDVWH FROOHFWLRQ DQG GLVSRVDO URXWHV DUH DOUHDG\ HVWDEOLVKHG 7KH FDWFK" 7KH RQO\ ODQG DYDLODEOH IRU WKH 05) IDFLOLW\ ZDV D P DUHD XQGHUODLQ E\ D P WKLFN PXQLFLSDO VROLG ZDVWH GHSRVLW ,Q DGGLWLRQ D P KLJK P builder’s rubble deposit laid over a portion of the site, with no land available on the site for it WR EH PRYHG WR $SSUR[LPDWHO\ RI WKH VLWH ZDV XQGHUODLQ E\ D P WKLFN PXQLFLSDO VROLG ZDVWH 06: GHSRVLW 'XULQJ WKH JHRWHFKQLFDO LQYHVWLJDWLRQ XQGHFRPSRVHG QHZVSDSHUV FRQͤUPHG WKH DJH RI WKH ZDVWH DV EHLQJ IURP WKH ODWH ̵V 1RW RQO\ LV 06: QRW a well understood geotechnical material, the waste deposit is highly variable by nature, with very different material properties

SRVVLEOH RYHU WKH HQWLUH GHYHORSPHQW DUHD ([FDYDWLQJ WKH ZDVWH DQG GLVSRVLQJ RI LW RQ WKH RSHUDWLQJ ODQGͤOO IDFH DQG LPSRUWLQJ RI FRPSHWHQW PDWHULDO ZRXOG QRW RQO\ KDYH UHGXFHG ODQGͤOO OLIH E\ P LW ZRXOG DOVR KDYH FRPH DW D FRVW RI 5 PLOOLRQ Adding in the cost of importation of competent new material at a FRVW RI DW OHDVW 5 PLOOLRQ WKH SURMHFW ZRXOG QRW EH IHDVLEOH XQOHVV DQ LQQRYDWLYH DQG XQLTXH VROXWLRQ FRXOG EH IRXQG E\ WKH WHDP The builder’s rubble had been collected by the City of Cape 7RZQ DW WKH ODQGͤOO RYHU WKH SDVW \HDUV DV SDUW RI DQ LQLWLDWLYH WR KHOS SUHYHQW LOOHJDO GXPSLQJ 7KH VWRFNSLOHV FRQVLVWHG RI YDULDEOH construction waste, including large rocks, concrete, and building PDWHULDOV ZLWKLQ D VRLO PDWUL[ At an early stage, JG Afrika recognised the importance of being innovative, and engineering sustainable solutions to the many SUREOHPV SRVHG E\ WKH VLWH Engineering the building platform as well as supporting the IRXQGDWLRQ ORDGV RI WKH VWUXFWXUHV ZHUH RQH RI WKH PDMRU FKDOOHQJHV WKDW IDFHG WKH GHVLJQ WHDP 7KH JHRWHFKQLFDO HQJLQHHU̵V LPPHGLDWHO\ ruled out supporting any of the main structures directly on a stiffened waste body due to the differential settlement risk, as well DV WKH LQFRQVLVWHQW QDWXUH RI WKH PDWHULDO $V VXFK DQ\ FRQYHQWLRQDO foundations would need to be founded on the underlying unconsolidated aeolian and beach sand deposits, which would not only be under the water table, but the OH&S risk of trenching P WKURXJK PXQLFLSDO VROLG ZDVWH PDWHULDO ZDV QRW DQ DFFHSWDEOH VROXWLRQ -* $IULND SUHSDUHG D SHUIRUPDQFH VSHFLͤFDWLRQ IRU WKH G\QDPLF compaction which required the appointed contractor (JVZ/SR Civils JV, using Franki as a specialist subcontractor) to achieve a bearing FDSDFLW\ DFURVV WKH HQWLUH VLWH RI N3D ZLWK D VWLIIQHVV PRGXOXV ( PRGXOXV RI DW OHDVW 03D WR EH YHULͤHG SRVW FRPSDFWLRQ E\ SODWH ORDG WHVW DQG &RQWLQXRXV 6XUIDFH :DYH &6: WHVWLQJ After conducting trials with different applied energies on site, the

dynamic compaction contractor was able to ascertain the energy requirements required WR PHHW WKH GHVLJQ VSHFLͤFDWLRQ ZLWK WKH SHUIRUPDQFH VSHFLͤFDWLRQ KDYLQJ EHHQ PHW E\ WKH FRQWUDFWRU WR GDWH ƒ • Company entering: JG Afrika • Client: City of Cape Town: Solid Waste Management • Civil Main Contractor: JVZ Joint Venture (JVZ Construction-SR Civils) • Dynamic Compaction Subontractor : Franki Africa PROJECT INFORMATION

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