Question: You are a structural engineer who has just been employed by a multi$-$disciplinary practice $($which includes architects, structural engineers, services engineers and quantity surveyors$).$ During the course of your first week at the office you have received the following four memos from people within your new company, all of which need answering as soon as possible. Provide an answer to suit, using drawings where appropriate to illustrate your answer.

Memo $1$ From: Christine Smith, Head Architect Subject: Lightweight flooring for new project Dear Ms$/$Mr Engineer, Welcome to the company. We are currently doing sketch designs for a new multi$-$storey office building $(25$ storeys$)$ in Perth CBD with a footprint area of approx. $30$m x $30$m$.$ We have the usual constraints of time and cost. The foundation material below the proposed building has a very low load bearing capacity so we must keep the weight of the building as low as possible. Can you please have a think about some alternatives for the type of structural frame for the building and more particularly the type of flooring system that would best suit these requirements? When you are ready give me a call to arrange a meeting.

Memo $2$ From: Janice Trimble, Architect Subject: Back$-$propping $*****$ URGENT $*****$ Hi Mr$/$Ms Engineer, Sorry, to do this to you in your first week here. I need some advice. I am supervising the construction of an eight storey hotel building. The frame and floors are being constructed by the contractor using traditional reinforced in$-$situ concrete. On my site visit this morning I noticed that the contractor was removing formwork and all props from underneath a slab that had been poured only $7$ days ago. I seem to recall that slabs should be back$-$propped but can't remember the full reasons or sequence required for back$-$propping. Can you please send me a sheet stating the purpose and a diagram showing the procedure so that I can pass it onto the contractor? I need the information urgently as I believe current site practices may be unsafe. Thanks.

Memo $3$ From: Sid Lately, Senior Architect Subject: New Development in Middle East Welcome Mr$/$Ms Engineer, I have been approached by a major Arab bank to design their new headquarters building in Oman in the Middle East. They have indicated that the building cannot exceed ten storeys due to local height restrictions. They want the building to be constructed as soon as possible and at minimal cost. I already have in mind some idea of shape and layout but am not sure which flooring system would be most appropriate. I am unfamiliar with the region and intend ringing the local Australian Embassy to find out more details about the area. Can you let me know what you want me to ask them in order to decide on the most appropriate system?