Construction World December 2021

strength, 90-minute pot l i fe and high flow propert ies that al lowed i t to be sel f-compact ing and for easy appl icat ion whether pumped or poured into place. The rapid strength gain of thi s product was cri t ical to the progress of the project . Heal th and Safety The large number of inherent safety ri sks associated wi th the works included, but were not l imi ted to, deep excavat ions , heavy crane l i f ts , working at height , working over flowing water and close proximi ty of ful ly operat ional regional route. To successful ly complete the project , these ri sks were requi red to be ef fect ively managed and mi t igated. During 2020, the COVID-19 pandemic led to the declarat ion of the nat ional state of di saster by the South Af rican government . Al l staf f were screened dai ly according to the agreed s i te guidel ines at the s i te camp. The works were audi ted monthly by Eppen-Burger & Associates for legal compl iance wi th the provi s ions of the Occupat ional Heal th and Safety regulat ions . The contractor maintained ful l legal compl iance throughout the project and averaged more than 92% on the monthly audi t compl iance scorecard for the durat ion of the contract . Envi ronmental Controls During the construct ion of the substructure and temporar y works various aspects were taken into cons iderat ion regarding the water management and di scharge of water in the river as requi red by the General Authori sat ion f rom DWS terms of the construct ion act ivi t ies and the ECO f reshwater special i st which related to water abstract ion l imi ts as wel l as requi rements for related to the qual i ty of water di scharged into the water course. The planning extended to sustainabi l i ty cons iderat ions by recycl ing the old fabric of the original bridge into the permanent foundat ion fi l l of the new bridge. Structural form and bridge aesthet ics received met iculous attent ion during the conceptual des ign wi th due cons iderat ion of the hi storical s igni ficance of exi st ing mul t iple-span arch bridge which also inspi red the structural form. 

re-assessment of the impl icat ions of the unexpected founding condi t ions was requi red. Through a mul t iple opt ion quotat ion, up to five des ign scenarios were tested in the market to assess the cost and programme aspects . Thi s led to a large diameter (>1 000 mm) pi l ing solut ion wi th approximate 10m length was adopted for the west abutment , wi th embedment wi thin the Us ing a transverse launching method of a completed concrete t ied-arch road bridge i s a fi rst in South Af rica where more than 8 000 tons of concrete and steel was moved over 24 m in less than 12 hours af ter several years of met iculous planning, des ign and construct ion. To instal l the sl iding and permanent bearings the 8 000 ton deck had to be vert ical ly l i f ted and lowered by H&I Construct ion. Thi s was done in phases by instal l ing the bearings at one abutment before repeat ing the process at the next . 12 No 500 t hydraul ic jacks were used for l i f t ing and lowering the deck per abutment . The launching of the bridge f rom i ts constructed pos i t ion to i ts final pos i t ion requi red a per fect ly level led sur face. Thi s was achieved by us ing Sikadur ®-42 ZA, high strength epoxy grout wi th i ts high compress ive strength and high abras ion res i stance. Tests wi th other products were per formed prior to appl icat ion, Sikadur ®-42 ZA met al l the stringent requi rements set out by the Project Engineers . Sikadur ®-42 ZA not only met the level l ing requi rements but could also be appl ied in a thin layer in a wide area wi thout having any shrinkage or cracking. The ent i re incremental launch went flawlessly to plan – wi th Sikadur ®-42 ZA being an important part of the success . The ul tra-high strength cement i t ious grout , SikaGrout ®-295 ZA, typical ly ut i l i sed in the under- steel baseplate grout ing of wind turbines on our local and internat ional wind farms , was used in several vi tal appl icat ions . Thi s included the grout ing behind the anchor plates and jacking f rames that created the permanent pl inths for the permanent bearings . SikaGrout ®-295 ZA was chosen for i ts ul tra-high competent Enon format ion. Transverse launching

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20 th Best Project Awards 2021