60x150 Steel Gymnasium Building

This page is ordered around zoning across the 60-foot span, because that is the dimension a steel gymnasium cannot change later.

The footprint holds 3 viewing sides — 1 across by 3 deep — and the remaining 6 feet is marginal: there is no concourse behind the seating, so spectators queue and stand at the floor edge.

Efficiency is the useful number here: 3,000 square feet of enclosed floor per viewing side, against a 1344-square-foot module. That is generous — the footprint is doing more than hold modules. What the building holds in its busiest week is the honest brief; the rest of the year is slack.

A 60 by 150 footprint is a long corridor of a plan: 9,000 sq ft enclosed by 420 ft of wall, at a 2.5:1 length-to-width proportion. Along its 150 ft dimension it takes 3 runs of viewing sides at 42 ft, leaving 24 ft over — the 24 ft is where the argument about this size actually happens. Taken purely as arithmetic, 60 by 150 gives 1 viewing sides across the 60 ft dimension once 18 ft is reserved for movement, and 3 deep along the 150 ft dimension. Run as a an activity floor with a permanent spectator side, 10 ft across is below the 14 ft this use needs to be worth planning, so there is no concourse behind the seating, so spectators queue and stand at the floor edge Sports floor construction is a separate specification from the slab, and the two are decided at different stages.

At 60x150 the operating question is a specific one: where do spectators sit, stand, arrive and leave without any of it happening on the activity floor? That is a different question from the one a steel gymnasium of another shape has to answer, and it is why this footprint is planned as an activity floor with a permanent spectator side rather than as generic covered area.

The activity pattern this floor could equally be planned around is a practice floor kept clear for training rather than for fixtures: there is no perimeter strip, so bags and equipment sit on the playing surface and the usable floor shrinks by more than the strip would have cost. One long side is given to viewing and everything that supports it; the activity floor keeps the rest. Splitting the seating across two sides doubles the routes required and halves the usefulness of each.

Treating the last 6 feet as a room is the recurring planning error at 60x150: there is no concourse behind the seating, so spectators queue and stand at the floor edge. Plan the exit as carefully as the entrance; buildings are emptied under more time pressure than they are filled.

Spare width is the more valuable of the two leftovers here: a continuous 28-foot strip beats the same area stranded at the end of the run, because it touches every position along the way. Interior divisions are the last decision that should be fixed, because they are the first one that usually changes.

Two populations move at once and must not mix: participants to the floor and its support rooms, spectators to the seating side. Separating them at the entrance is the decision that governs the plan. The dimension that constrains an activity building is the clear height over the whole floor, not the floor area. That movement pattern, not the 9,000-square-foot total, is what decides whether the leftover 6 feet is useful here.

At 60 feet the gable will not comfortably take one opening per viewing side: 1 position with 28 feet spare leaves too little wall for piers. A single wider opening, or a sidewall opening, is the workable route. Depth is bought cheaply and width expensively, which is why this proportion tends to be argued about before anything else.

The 60 ft ends and the 150 ft sides offer very different opening budgets: 60 ft of end wall has room for one wide opening or two modest ones, while 150 ft of side wall can carry several without the openings competing. On this plan the deciding factor is whether spectator side planning or concourse layout should be the first thing reached from the door.

Nominal bay division computes to 6 bays at about 25 feet, narrower than the 32-foot module — so frame lines land inside positions and the interior has to be set out from the columns. Utilities entering on the wrong elevation quietly rewrite the interior layout.

Two-plus rows change the access question entirely. Every rear position at 60x150 needs either its own opening or an aisle, and 28 feet of spare width is what that aisle has to come from. Insulating later is possible; framing for insulation later is much harder.

Extension is cheapest along the 150 ft dimension, where each added bay repeats work already framed; widening past 60 ft is a different frame rather than a longer one. Growing to 60 by 192 adds a 4th run of viewing sides — useful if the constraint is viewing sides rather than the 24 ft already spare at the far end.

Configured as an activity floor with a permanent spectator side, 60x150 is judged on whether the 3 viewing sides it holds match the operation, and on whether the 28 feet of spare width leaves the route this mode depends on.

• Does the work need four lanes across, or two lanes flanking an interior work hall, or does it need a second lane that this 60-foot span cannot give?
• Is the 150-foot length being bought for depth, or for the repeated bays — a long repeating bay sequence, so segment boundaries are set by bay lines rather than by walls?
• What clear height does the activity need, measured to the lowest obstruction?
• Are the run-off margins protected from storage and seating?

Across a 60-foot span the 3:12 pitch adds 7.5 feet between eave and ridge. The centreline measures 21.5 feet; anything parked or stacked near a wall lives with the 14-foot eave. Long spans buy flexibility that is only worth paying for if the operation actually changes shape.

Sightlines add a vertical dimension the plan alone does not show, and raked seating raises the height needed at the back of the viewing side beyond what the floor requires.

Ventilation across 9,000 square feet at this height: an intensively occupied volume with high activity levels, where air handling is planned for the occupied peak.

• 60x60 moves the count from 3 to 2 viewing sides (2 across by 1 deep), which is the reason to choose between them.
• 50x80 moves the count from 3 to 2 viewing sides (1 across by 2 deep), which is the reason to choose between them.
• 40x100 moves the count from 3 to 2 viewing sides (1 across by 2 deep), which is the reason to choose between them.

Because this footprint is planned as an activity floor with a permanent spectator side, the useful next reads are different from the ones a differently shaped steel gymnasium suggests: spectator side planning, concourse layout, separated entry routes.

The estimate at 60x150 moves with four computed quantities: 9,000 square feet of floor, 420 feet of perimeter, 5,880 square feet of wall and 9,277 square feet of roof. Everything else is site and specification. Height is the dimension people regret; it cannot be added later without rebuilding the frame line.

Seating, its structure, the concourse and the additional sanitary and egress provision are a substantial addition to a plain activity building rather than a finishing item.

• clear height above the playing surface
• the clear span across the court and its run-off
• the support wing with changing rooms
• impact-resistant lighting and interior surfaces