Systems in Timber Engineering (eBook)

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Josef Kolb was Director of Technology for Lignum in Zurich and has been active in many areas for a number of years as an outstanding expert with his own engineering firm specializing in timber construction.

Josef Kolb war Leiter Technik bei der "Lignum" in Zürich und betätigt sich seit mehreren Jahren vielseitig als exzellenter Fachmann mit eigenem Ingenieurbüro im Bereich Holzbau.

a. Principles. Material-related 9
a1 Wood - natural building material with potential 10
a1 10 Progress rooted in tradition 10
a1 20 Timber engineering 13
a1 30 Facade 15
a1 40 Fitting-out 17
a2 Ecology, sustainable building 18
a2 10 Wood - a building material with ecological benefits 18
a2 20 The wood life cycle and processing chain 18
a3 Conception and design 22
a3 10 The design process 22
a3 20 Planning 25
a3 30 Process sequence 27
a3 40 Quality assurance 28
a4 Material 32
a4 10 Species of wood 32
a4 20 Properties of wood 33
a4 30 Grading 34
b. Construction systems. Loadbearing structure, building structure, design 37
b1 Overview of systems 38
b1 10 Building systems in timber construction 38
b1 20 Walls, suspended floors, roofs 40
b1 30 Choosing a building system 41
b2 Fabrication processes 42
b2 10 Fabrication processes related to building systems 42
b2 20 Building principles 44
b2 30 Fabrication stages related to the building components 46
b2 40 Building with elements 47
b3 Log construction 50
b3 10 General 50
b3 20 Further development 51
b4 Timber-frame construction 54
b4 10 Past and present 54
b4 20 The parts of the construction 56
b4 30 Settling allowance 57
b5 Balloon frame, platform frame 60
b5 10 Two basic forms 60
b5 20 Timber stud construction today 61
b6 Panel construction 62
b6 10 General 62
b6 20 The parts of the construction 64
b6 30 Settling allowance 65
b6 40 Building structure and wall construction 66
b6 50 Structural engineering 78
b6 60 Loadbearing construction 82
b7 Frame construction 86
b7 10 General 86
b7 20 The parts of the construction 88
b7 30 Building structure 90
b7 40 Forms of frame construction 94
b7 50 Structural engineering 106
b7 60 Loadbearing structure and building envelope 108
b8 Solid timber construction 112
b8 10 General 112
b8 20 Solid cross-sections 114
b8 30 Compound cross-sections 128
b9 Roof structures 136
b9 10 General 136
b9 20 Overview of structural systems 140
b9 30 Close-couple roof 142
b9 40 Purlin roof 146
b9 50 Traditional roof structures 150
b9 60 Roof trusses, trussed rafters 152
b9 70 Roof systems with primary and secondary structures 154
b9 80 Structural engineering 156
b10 Suspended floor structures 158
bl0 10 General, overview of systems 158
bl0 20 Structural engineering, loadbearing construction 160
b10 30 Construction details 164
b10 40 Technical materials requirements 170
b10 50 Timber joist floors 172
b10 60 Ribbed-panel and hollow-box floors 174
b10 70 Solid timber floors made from solid timber sections 176
b10 80 Solid timber floors made from board-type, glued elements 178
b10 90 Timber-concrete composite floors 180
b11 Multi-storey timber buildings 182
b11 10 General 182
b11 20 Conception and design 184
b11 30 Structural engineering 185
b11 40 Settling behaviour 194
b11 50 Typical sections 198
b11 60 Building services 200
b11 70 Production 200
b11 80 Erection 200
c. Building envelope, walls, suspended floors. Functions, layers, construction 201
c1 Fundamentals, functions, tasks 202
c1 10 General 202
c1 20 Building envelope 204
c1 30 Functions, tasks, and performance 208
c1 40 Building standards 222
c2 Design and construction 224
c2 10 General 224
c2 20 Positions of component layers 225
c2 30 Junctions between components 228
c3 External walls 234
c3 10 External wall systems 234
c3 20 External cladding 238
c3 30 Inner linings 244
c4 Pitched roofs 246
c4 10 Uninsulated pitched roofs 246
c4 20 Insulated pitched roofs 246
c5 Flat roofs 254
c5 10 Uninsulated flat roofs 254
c5 20 Insulated flat roofs 255
c5 30 Design of insulated flat roofs 260
c5 40 Falls 261
c6 Party walls, internal walls 262
c6 10 Tasks 262
c6 20 Sound insulation of party walls 263
c6 30 Flanking transmissions 265
c6 40 Suggested forms of construction 266
c7 Suspended floors 270
c7 10 Tasks 270
c7 20 Sound insulation of suspended timber floors 270
c7 30 Flanking transmissions 275
c7 40 Suggested forms of construction 275
d.Boundary conditions. Moisture content, protecting timber, fire protection 285
d1 Moisture content 286
d1 10 General 286
d1 20 Requirements 286
d1 30 The right installation moisture content 287
d2 Protecting timber 288
d2 10 Risks 288
d2 20 Constructional (passive) protection 289
d2 30 Surface treatments and chemical wood preservatives 291
d2 40 New developments in protecting timber 295
d3 Fire protection 298
d3 10 Fire protection in the planning process 298
d3 20 Fundamental terms 298
d3 30 Requirements 301
d3 40 Design 306
e. Appendix. Disclaimer, notes, references 309
e1 References, institutions 310
e2 Information, databases of manufacturers 312
e3 Regulations, standards, technical information sheets, aids 312
e3 10 Switzerland 312
e3 20 Germany 313
e3 30 European building materials and products standards 313
e4 Further reading 313
e5 Picture credits 314
e6 Construction projects featured in photographs 315

a3 Conception and design (p. 23-24)

Detailed design

Detailed design means turning the conceptual ideas, the draft design, into clearly defined sizes, dimensions, layers and their arrangement, at the same time specifying junctions and details. In doing so, the interactive process between conception and design must always be taken into account, as mentioned above. The ideas often emerge out of the draft design, but the feasibility becomes apparent during the detailed design. During detailed design, the building work is given a clear configuration. Concerning the loadbearing structure the aim is to satisfy the requirements in terms of load-carrying capacity and serviceability. In the case of the walls, roofs and suspended floors, besides the structural engineering requirements, it is the building`s physics and energyrelated requirements that have to be coordinated with and optimised for the intended use.

Important conditions for simple interfaces between conception and design are a draft design coordinated with the timber building on plan (grid dimensions) and in section (storey heights) and from that the maintenance of system heights and component dimensions. Larger structural depths for suspended floors result in, for example, simpler and more economic constructions and at the same time offer space for services. Section b10 "Suspended floor structures" specifies typical system depths for the loads of residential and office buildings plus places of assembly. The grid dimension likewise influences the loadbearing system of a large timber building with respect to component dimensions and the number of joints.

Another conception and design rule is that component and functional layers should continue uninterrupted through the wallground floor and foundation, wall-wall, wall-suspended floor and wall-roof junctions. Contemporary conception and design therefore calls for coordinated concepts or systems for thermal performance, fire protection, sound insulation, moisture control, airtightness, etc. at the draft and detailed design stages.

In addition, through the skilful conception of plan and section it is possible to meet ideal sound insulation and fire protection requirements right from the draft design stage. The detailed design phase allows the architectural, technical, economic, and ecological conditions to be refined and optimised. Also important are the criteria of durability and maintenance. Good solutions can be achieved by choosing a suitable building form, well-thought-out designs and intelligent details. Added to this is the choice of species of wood and the surface finishes, possibly also precautions for chemical wood preservatives.

a3 20 Planning

Owing to the increasing industrial fabrication of timber structures, there has been a shift in the chronological order of the critical decision- making process of architects, engineers, specialists, and contractors. Things that in the past were first discussed on the building site, must now be specified well in advance of fabricating the walls, suspended floors, and roofs. Fig. a37 shows the planning, production and erection sequence (in weeks) for a medium- sized timber building in comparison with the conventional approach, which is frequently still the situation with masonry or concrete buildings.