45179_towardssaferschoolconstruction_0 2015 - Page 73

Prior to designing a school building, the design team needs to understand the outcomes of the Planning Stage – the needs assessment, feasibility study and draft implementation plan. They need to meet with the school management committee and potentially other community stakeholders. They also need to visit the selected site to conduct detailed investigations o f its characteristics. This pre-design consultation phase, which for smaller projects may occur as part of the Planning Stage, should address three major design considerations: • School site investigation. The design team needs to confirm some of the assumptions made at Planning Stage by visiting the selected site. They may conduct a local site survey to verify hazards, the shape of the site and soil characteristics. From this, they can layout classrooms and other facilities to fit within the site, and they know how big the foundation needs to be to support the building on the specific soils found at the site. The design team also needs basic information, such as the height of the water table and vegetation on the site, to determine what type of site preparation and drainage is needed. In seismically active and landslide zones, the softness of the soil defines how intensely a school building will shake or whether the soil under the building will destabilise the structure. Regional and local soil maps may provide a general overview of site conditions, but often these maps are insufficient for structural design. Geologists or geotechnical engineers should investigate local site conditions. • Building performance objectives. Performance objectives define how well the school building will perform during hazard events. Buildings, at minimum, should be designed to be ‘life safe’ for known hazard events. For example, national design codes or other guidelines may require all school buildings to withstand high winds or earthquakes of a certain size or frequency. A building designed to be ‘life safe’ in these events would not collapse (partially or completely) or cause fatalities during that event. However, the building may sustain high damage and need extensive repairs or complete replacement after the event. • Community context. Design teams should also meet with the school management committee to understand the needs and aspirations identified by the committee during the Planning Stage. The committee’s vision for the school should shape what the design team prioritises. The design team should understand the local materials, construction practices and labour capacity. Local tradespeople may not have the expertise to execute sophisticated construction techniques – for example, dampers in a frame or composite construction materials – no matter how hazard-resistant and innovative they may be. Designs that build on local practice and make only moderate adaptations to local building styles and materials are more effective because they ensure communities can retain these good practices and apply them elsewhere. Balancing cost and performance objectives in flood plains and storm surge zones Schools in flood plains and storm surge inundation zones can be built so they remain structurally intact even when inundated. However, inundation precludes the use of the school as a shelter. Stakeholders may decide to invest in a more costly, elevated school so that it remains undamaged in a flood event. Built to a higher performance objective, this school could serve as a community shelter post-hazard. Alternatively, stakeholders may decide to construct a less costly school, with the knowledge that they will need to clean mud and debris out of the school before using it again. Staff and students can evacuate and save educational supplies, but the building will not be suitable for shelter or immediate occupancy. Development actors and government agencies may take a regional approach, ensuring communities can all access a school designed to higher performance standards in their region, even if the schools closest to them are designed to lower standards. SECTION III: DESIGN Key activity 1: Pre-design community consultation The school management committee and wider community stakeholders may decide a ‘life safety’ performance objective is insufficient. Higher performance objectives, such as ‘cyclone shelter’ or ‘immediate occupancy’ could make more sense when the school building is intended for shelter during or after a disaster. It is also important for enabling students to resume education in the building immediately after the disaster. Buildings adhering to these higher standards have higher construction costs but experience much less damage in disasters. The community needs to understand the performance objective options and weigh them against resources and community needs. The implementing actors may also require higher performance objectives based on regional or emergency response planning. 64