The existing cricket and athletics stadia at Queen's Park Grenada suffered significant structural damage during the recent Hurricane Ivan, which hit the island on 7 September 2004.

In particular, collapse of the roof structures to the three principal, pavillions, and major damage to all other roofs has occurred. Prior to this event, Arup Associates, architects and engineers, had been engaged in the design of the proposed redevelopment of the cricket stadium for the hosting of the Cricket World Cup West Indies 2007.
The Grenada Local Organising Committee has therefore asked Arup Associates to provide a structural report on our observations on the damaged structure and the impact on the redevelopment proposals.

Despite the initial overall impression of a scene of devastation, the significant damage mainly concerns the collapse of the main and secondary pavilion steel roof structures, and partial loss of other roof structures and roof cladding.

The primary reinforced concrete framed construction appears principally intact, other than minor damage resulting from the falling roof structures. Additionally, with the loss of weather-tightness, fixtures and fittings have subsequently also become damaged.

Main Pavilion

_ Rotation collapse of roof, through failure of supporting columns.

_ Secondary damage to parts of reinforced concrete frame and walls from falling roof structure.

_ General damage to fixtures and fittings, both from the event, and subsequent water ingress.

Main Pavilion

_ Overturning collapse of roof, through failure of supporting columns

_ Secondary damages to parts of reinforced concrete frame and walls from falling roof structure.

_General damage to fixture and fittings, both from the event, and subsequent water ingress

Players Pavilion

_ Partial collapse of roof, and loss of roof cladding.

_ Secondary damage to parts of reinforced concrete frame and walls from falling roof structure

_ General damage to fixtures and fitting, both from the event, and subsequent water ingress.

Media Pavilion

_ Substantial collapse of roof

_ Secondary damage to parts of reinforced concrete frame and walls from falling roof and structure

_ General damage to fixtures and fittings, both from the event, and subsequent water ingress.

Scoreboard

_ The structure has overturned, there having been no apparent holding down arrangement.

Mode of Failure

All three pavilion roofs were seen in the site inspection to have collapsed as a consequences of structural failure of the key column at its connection to the upper seating tier frame.

Adequacy of the Original Design

There are several issues that cause concern about the adequacy of the original design, which suggest that failure was premature and not the result of exceptional wind loading.
The roof structures collapsed with cladding almost fully intact. This would suggest that failure occurred at a relatively low wind speed, as a robust structure under extreme wind loading would normally exhibit significant cladding loss prior to structure damage.

Conclusion of Failure Mode

Despite the extreme nature of the wind conditions experienced during Hurricane Ivan, there is circumstantial evidence provided by surviving structure elsewhere ... that modern structure designed robustly in accordance with the current provisions of the wind loading codes should have survived without significant structural collapse.

We believe that there is significant evidence, as described above, to conclude that the collapse of the roof structures of the three main pavilion was premature. Our view is that this was due to a lack of design appreciation of the key element nature of the supporting concrete columns, which in our assessment do not have the design capacity to satisfy the code requirements in force at the time.

Additionally, reinforcement detailing of laps at the point of maximum bending moment is not in accordance with good practice, and together with poor control of site fixing, has contributed to the failure of the columns.

Demolition and clearance of damaged structure

The most significant damage is to steel roof structures, with the complete loss of the main and secondary pavilion roofs, and major damage to all other roofs. The concrete stand superstructures are largely intact, however, suffering only secondary damage due to the falling roof structure and other minor cosmetic damage.

Roof structures would therefore need to be carefully removed in a controlled sequence to avoid further damage to stand structures, and enable safe assessment of their potential to be repaired and retained in the proposed new development for Cricket World Cup 2007.

Main Pavilion

The two 100 m x 22 m cricket and athletics pavilions, which are situated back-to-back, have both lost their entire roof structures. The cricket roof has fully overturned, fallen into the shared concourses area, and lies against the back of the athletics roof, which fell forward over the seating stand below.

The demolition approach therefore needs to be one of 'de-construction', and to involve a sequence of temporary support to safely enable the cutting of the roof into smaller sections, which can be lifted clear and removed from site. Access to install propping and effect cutting operations in a safe way would need to be very carefully considered, and large crane support is anticipated.
Manual access should be from above only, by cherry picker or similar equipment. This may be more straightforward for the athletic roof, but will be more complex for the cricket roof, which has fallen into the concourse between the two stand.

More extensive demolition of the secondary structures within the concourse area to facilitate access is anticipated. A sequence of demolition is envisaged as follows:

Additionally, reinforcement detailing of laps at the point of maximum bending moment is not in accordance with good practice, and together with poor control of site fixing, has contributed to the failure of the columns.

Demolition and clearance of damaged structure

The most significant damage is to steel roof structures, with the complete loss of the main and secondary pavilion roofs, and major damage to all other roofs.

The concrete stand superstructures are largely intact, however, suffering only secondary damage due to the falling roof structure and other minor cosmetic damage.

Roof structures would therefore need to be carefully removed in a controlled sequence to avoid further damage to stand structures, and enable safe assessment of their potential to be repaired and retained in the proposed new development for Cricket World Cup 2007.

Main Pavilion

The two 100 m x 22 m cricket and athletics pavilions, which are situated back-to-back, have both lost their entire roof structures. The cricket roof has fully overturned, fallen into the shared concourses area, and lies against the back of the athletics roof, which fell forward over the seating stand below.

The demolition approach therefore needs to be one of 'de-construction', and to involve a sequence of temporary support to safely enable the cutting of the roof into smaller sections, which can be lifted clear and removed from site. Access to install propping and effect cutting operations in a safe way would need to be very carefully considered, and large crane support is anticipated.
Manual access should be from above only, by cherry picker or similar equipment. This may be more straightforward for the athletic roof, but will be more complex for the cricket roof, which has fallen into the concourse between the two stand.

More extensive demolition of the secondary structures within the concourse area to facilitate access is anticipated. A sequence of demolition is envisaged as follows:

(1). Make working area safe, and remove any loose elements of structure

(2). Remove roof sheeting and purlins where accessible from above

(3). Provide crane support for truss to be removed, as well as for adjacent truss.

(4). Cut/disconnect steel secondary framing, working only from above via cherry-picker

(5). Lift and remove truss

(6). Progress work sequentially from one end to the other

(7). Inspect concrete structure damage once clear

(8). Remove damaged concrete elements

(9). Clear ready for reinstatement works.

Players Pavilion

The 20m x 15m three-storey reinforced concrete frame building is generally intact but has suffered significant damage to the steel cantilever truss roof structures. The remaining roof structure therefore needs to be removed, this can be carried out by a method of crane support and unbolting.

Media Pavilion

The 20m x 15m three-storey reinforced concrete frame building is generally intact but has suffered significant loss to the steel cantilever truss roof structures.

However the existing building is considered inappropriate for the known media brief requirements of Cricket World Cup 2007. It is therefore proposed that the complete building will be demolished.

Covered Bleacher F

The 100m x 13m covered bleacher had a more robust roof system, consisting of a steel column and backstay support for the steel cantilever truss roof, which is till standing. The majority of cladding was lost and parts of the framing have been distorted by the extreme wind loading. Anchoring connections of the backstay have pulled out of the concrete stand in some cases.

It is considered that repairs of the roofs in-situ is not practical and removal of the complete remaining roof structure is therefore recommended. The roof structure demolition could be carried out by crane support and unbolting of the approximately 1 tonne 13m long steel trusses, and should be a relatively straightforward operation.