31-03-2014, 11:44 AM
Leeds Arena: Big noise in the city
Big noise in the city[.doc (Size: 997 KB / Downloads: 15)
How Bam kept the noise down in the 12,500-seat arena in Leeds city centre
Forget battles of the bands, in Yorkshire the real war is all about whether Sheffield or Leeds can host the best entertainment arena. Sheffield already has a venue and is concerned that the new 12,500-seat Leeds Arena under construction 34 miles away in the city of Leeds is going to hit revenues when it opens next year. Sheffield is fighting back, citing its convenient location next to the M1 as an advantage, and adding that the Leeds arena’s city centre location will be a nightmare for music-goers. But Leeds sees a central location as a positive and believes the unique, fan-shaped seating layout around a stage at the back rather than the centre of the arena will give spectators the best views and acoustic experience anywhere in the UK.
However, the combination of location and acoustic performance did present problems - specifically, how to keep the noise at an acceptable level for those living close by. Planning conditions stipulated that external noise levels had to be 10dB lower than ambient noise levels outside the building, a criterion which doesn’t come cheap on a building big enough to swallow a football pitch. The job was tendered as a two-stage design-and build contract, after the council had worked up the design using its own team, headed up by Jacobs. Bidding contractors, which included winner Bam, had to satisfy themselves that the building could be delivered for the council’s budget of £60m.
HOW BIM HELPED BAM
The complexity and size of this job persuaded Bam to use it as a Building Information Modelling (BIM) trial project. It wanted the design team and supply chain to use BIM and monitored how much time and money it saved by comparing it to an earlier Leeds Metropolitan University project which employed the same project team. Engineering consultant Arup was happy using 3D modelling but architect Populous was still using 2D drawings. Some of the supply chain including steelwork specialist, Fishers, precast specialist Creagh and cladding specialist Lakesmere were already using 3D modelling.
Bam calculated that by drawing virtually in the BIM model, it saved the issue of 9,000 drawings. It also cut back on the need for design meetings by 75%, which saved 1,500 hours. The total design time saving added up to 15,000 hours. This had the added benefit of saving the 60,000 miles that would have been crossed travelling to those meetings.
According to Bam, a job of this size would typically involve 1,000 major site-based clashes. It reckons that 90% of these would be discovered during the design phase with 100 slipping through the net. Bam estimates that each clash would cost an average of £3,500 to resolve on site which adds up to a theoretical cost of £350,000.
Have these costs been avoided on site? “BIM has made a tremendous difference and was highly beneficial for the structure,” Alexander says. He says there were only two clashes between the steelwork and the precast elements. Some of the steelwork was too high in one area and a few of the angles used to support precast elements were in the wrong position. “It was a day’s work to reposition these,” he says.