“The Hordern” as it is affectionately known by Sydney-siders, has been an architecturally and socially significant Sydney landmark since its construction in 1924. Best known as a rock concert venue, the Hordern Pavilion was originally constructed to meet the increasing demands for exhibition space at the Royal Easter Show.
The Pavilion was named in honour of the enterprising retail family Anthony Hordern and Sons. The building is designed in the inter-war Academic Classical Style with rendered masonry featuring classical detailing inside and out, including fluted Doric columns, a parapet and an imposing vaulted roof with lantern tower. It cost 45,000 pounds (approximately $A74,000) to build.
The first exhibition held at the Hordern Pavilion was a celebration of the progress of industry, technology and enterprise. Electric lights, wireless broadcasting and the latest motor cars were among the exhibits. In 1972 the Hordern Pavilion was modified to make it more versatile. Most of the columns were removed and replaced with a new truss system, false ceilings were introduced and a bar and ticketing boxes, together with a mezzanine corporate box area, were constructed.
“The rock scene came surging back and the Hordern was the epicentre,” says Glen A Baker.
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“One amazing moment came when a certain Norman Gunston, aka Garry McDonald, climbed onstage and played harmonica with Frank Zappa and the Mothers of Invention.”
Sweet problem
The Hordern Pavilion was constructed over an old 381 mm x 254 mm Sydney Water oviform sewer and one of the access chambers had ended up in the middle of the floor inside the building.
Sydney Water Corporation, in common with other major authorities, has a number of critical sewer mains of oviform shape. While this egg shape has the advantage of providing a self cleaning velocity at low flows, the same shape makes it very difficult to design and install a lining that will restore structural strength to the sewer without loss of flow capacity.
The section of the sewer to be repaired had been previously rehabilitated with a cured in place pipe (CIPP) lining and everything was fine until some ready-mixed concrete slipped into one of the access chambers. This concrete then set hard inside the pipe and was discovered during a CCTV inspection of the pipe.
Sydney Water had no alternative but to try and remove the concrete to prevent potential sewer overflows. The hardened concrete was successfully ground away but unfortunately the lining was damaged in the process. The section from outside the building to the access chamber inside was found to be seriously damaged.
Kembla Watertech was approached by Sydney Water and asked to provide a repair proposal to restore full structural strength to the sewer without disruption to activities at the Hordern Pavilion. Enter Trenchless Technology stage right.
Because it was only the first length under the building that was damaged, access to the chamber within the building would be required. It was immediately evident that this could create a serious issue of odour emission into the interior of the building as soon as the access chamber cover was removed.
The two fold response
Stage 1: prepare the pipe for a new structural lining
A robotic cutter connected to a CCTV camera was used to mechanically remove the damaged sections of liner without causing any further damage to the existing sewer pipe.
Access for the cutter and CCTV was gained from an access chamber outside the building, which meant that the access chamber lid inside the building did not need to be opened. This work was made more difficult by the oviform shape and the cutter and camera had to be modified to make them traversable inside such a shape. While the work was time consuming the first stage was completed successfully without any incident.
Stage 2: supply and install a new lining
Kembla’s Enviroliner system is a CIPP method for the renovation of pipelines by the installation of a resin impregnated flexible tube which is inverted into the existing conduit by the use of hydrostatic pressure.
The tube is cured to a hardened state while held in intimate contact with the conduit. CIPP linings are tailor made to suit the circumference of the pipe and because they are inserted in a softened state they will take the shape of the host pipe. This makes CIPP ideal for non circular shapes such as oviform.
Measurements were taken and a replacement CIPP lining was specially fabricated to suit the internal circumference of the oviform pipe.
Installation of CIPP lining is a common place event and the main issue with this installation was one of customer relations and the potential for odours entering the building when the sewer was accessed.
Kembla prepared site specific customer relations and hazard control strategies for this work which were submitted and approved by SWC before work began.
In keeping with the Hordern Pavilion theme, Kembla erected its own ‘stage’– a fully enclosed tent was erected over the access chamber inside the building. This tent contained portable extraction fans and ductwork which ventilated any odours emanating from the sewer to the outside atmosphere.
The new 73 metre length of lining was installed from an access chamber outside and finished at the access chamber inside. Once fully hardened the lining ends were cut off and the sewer flow reinstated.
The complete set and installation was completed in a two day period which complimented the functions schedule of the Hordern Pavilion. Again, the work was completed successfully without any incident.
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