Course 4

Materials for industrial building structures

“Gh. Asachi” Technical University, IaşiFaculty of Civil Engineering

Department of Civil Engineering

dr. Gabriel OPRIŞAN

Outline presentation•Reinforced concrete for industrial buildings

• Structural steel for industrial buildings

The concrete for reinforced concrete members orstructure must have the required strengthrecommended by the design engineer, provide a goodbond with reinforcement and have an adequatethickness to protect the steel bars against corrosion.

Usually, concrete has several advantages, such as:

• It is very strong in compression;

• Allows for architectural uniqueness;

• Materials to make concrete are cheap and easilyaccessible;

• It is very easy to prepare, even on site.

In case of mass production of RC elements, theprefabrication technique is the most efficient method if weconsider the production process and labour requirements,which are kept at reasonable costs.

The advantages of precast concrete elements are:

• Control of the quality of concrete

• Smoother surfaces and plastering is not necessary.

• Less storage space is needed

• Concrete members can be cast under all weatherconditions

• Better protection for curing.

• Weather conditions do not affect erection.

• Faster erection time.

As a rule, RC industrial buildings are framebuildings and RC frames serve as the main load-carrying elements. Table 3.2 shows the designstages of a RC frame structure correlated to thecurrent national procedures.

Stages of the RC frame structural designNP 007-97. “Cod de proiectare pentru structuri în cadre de beton armat”, IRS.

Reinforced concrete girders

Often precast RC girders with solid core are used as well asprimary beams, secondary beams, girts, purlins, runway girders,forming parts of the structure of an industrial building.

The differences between prefabricated RC girders and monolithRC girders consist in that the reinforcement and the concrete maybe efficiently distributed with respect to the neutral axis andlongitudinal axis of the girder; consequently, important reductionsof materials and lighter RC elements can be achieved.

For prefabricated RC girders prestressed systems withpretensioned reinforcement can be applied.

Compared to monolith girders, which have rectangular or “T”cross-section with width of the web between 20…35cm being thedistance imposed by the casting possibilities and compaction ofthe concrete, the cross-section of prefabricated RC girders canhave different shapes, illustrated in fig.3.10

Figure 3.17 Different types of cross sections for precast RC girders [Mihul, 1969].

The main data used to design RC industrial halls withtransverse girder can be found in the specializedcatalogues elaborated by IPCT(Catalogue 5435 C2),together with other important information regardinggirder types, load capacity, elevation and section ofelements, plan view, design steps of an RC industrialstructure, assembling requirements, etc. Fig.3.18 presentsthe elevation of a prestressed RC transverse girder andtwo cross sections to the end and middle of the girder

An important category of construction elements used for industrialbuildings with cranes are the runway girders. The runway girdersare subjected to dynamic actions. These kinds of elements can bemade of steel, reinforced concrete and prestressed concrete.Prefabricated runway girders made of reinforced concreteor prestressed concrete are rational for travelling cranes withmedium work regime and the capacity up to 500 KN.

In order to adopt the transverse section, the vertical orgravitational loads and horizontal forces resulted from thetravelling crane must be considered.

That is why the RC runway girders with a 6 meter span will bedesigned with a “T” section, and prestressed girders with double“T” section.

Because of the rigidity condition and for economical reasons, theheight h of the runway must be 1/7...1/8 of the span L, and thewidth of the flange b=1/20 of span L.

The runway system contains the following elements: runwaygirder, rails (members that sustain the travelling crane, providinga part of the rigidity on longitudinal direction of the industrialbuilding), sleepers, metal plates (fig.3.20).

Figure 3.20 Connection details between railsand RC railway girders

3

80 20 375

375

75

375

375 37

537

537

537

537

5 375

375

375

375

375

375

b c d

b c da a

bumper

View a-a

b-b c-c d-dRailway

DetailSleeper14x20x300

RailwayRC girder

RailwayRC girder

RailwayRC girder

Metallicplate

Metallicplate

Fixing M24 bolt

Cross section of runway girders

3.4.1.2. Reinforced concrete columns

RC columns are structural members where the main loadis compression. Compared to metallic columns, RCcolumns are more economical because the steelconsumption is 80% less, and the cost is lower by 40%.

The distribution of RC columns in the plane ofconstruction is recommended to be as uniform as possible[NP 007-97]. Determination of sizes and checking of RCcolumns must be in accordance with the RomanianStandards [STAS 10107/0-90, pt. 3.]

Several types of precast RC columns are presented infig.3.21. Columns of single-storey buildings are designedin solid shapes, with a rectangular or “I” section or withopen webs with two branches, fig.3.22.

3.4.1.2. Reinforced concrete columns

a. b. c. d. e.

Precast RC columns usedfor the construction ofindustrial buildings: a., b., e.columns for single-storeyindustrial buildings; c., d.columns used for single-storey industrial buildingswith travelling crane

Connections of roof members columns

Reinforced concrete columns for industrial halls (single storey structures)

a. Without travelling crane; b.,c. d.R.C. columns for travelling cranes

Reinforced concrete members of a single-storey industrial building

Reinforcement of eccentrically compressed columns

3.4.1.3. Reinforced concrete roof elements

The prefabrication techniqueallowed the use of prestressed RCelements because they have largespans and rational make-ups,ensuring the co-working betweenthe RC plates and RC girders.Fig.3.23 presents RC roofelements and table 3.3 providesgeometrical data, weight, capableloads and the project type.

a.

b.

c.

d.

e.

3.4.1.4. Reinforced concrete foundations

The Romanian design guide NP112-04 contains completeinformation about the design and making up of RC pockets.Fig.3.24 illustrates the horizontal and transverse sections of a RCisolated pocket foundation.

3.4.1.4. Reinforced concrete foundations

The dimensions of the hollow pocket foundation must be largerthan the cross-section of the RC column in the following way:

• by 50÷75 mm for the base of the pocket foundation• 85÷120mm for the upper part of the RC pocket foundation.

The joining between the RC column and the foundation aremade by concreting the space from the pocket foundation with aminimum class of concrete C16/20 having the dimensions ofaggregates of maximum 16mm.

Reinforced concrete foundations

1. trunchiului exterior de beton armat;2. Nervura interioara a trunchiului3. Plafon b.a. 1m grosime4. Placa de baza din b.a.5. Placa beton precomprimat6. Inel din beton armat

3.4.2. Structural steel for industrial buildings

The structural steel is one of the most efficient materials used for theframing systems of industrial buildings. Steel as a structural materialhas several advantages that allow for maximum design flexibility:• it is produced in a wide range of shapes and grades;• offers the highest strength-to-weight ratios of any current materialfor structural systems;• it is dimensionally stable and its durability is not affected byalternate freezing and thawing;• it is 100% recyclable;• can be designed for long spans which create more open floor plansof industrial buildings;• is a non-combustible material and its strength remains stable up to3000C;• a steel industrial building is erected fast and there is virtually no"wet" work;• the design of steel industrial buildings leads to efficient and safestructures in seismic conditions;

Since 1873, hot-rolled steel sections have been used to build thesingle-storey shed frames, having as the main destination factoriesand warehouses. In the first stage these shed frames consisted ofbrick side walls or steel columns supporting triangular trusses andhaving the roof slope at 200. The triangular truss supports purlins,rafters and slate roofing (fig.3.25).

Figure 3.25 Symmetrical pitch steel roof on steel columns

Figure 3.26 North light lattice steel roof on steel columns

In order to obtain large spaces and to minimise the number of internalcolumns, the cantilever roof or the umbrella can be adopted (fig.3.27).

Figure 3.27 Symmetrical pitch lattice steelcantilever (umbrella style) roof on steel columns

Figure 3.28 Lattice girder flat roof withsecondary steel beam on steel columns

Portal frames made of steel, fig.3.29, are an alternative solution withlow material consumption to reduce the unusable roof space that mustbe heated supplementary.

Figure 3.29 Large span steelportal frame

Figure 3.30 Single span symmetrical pitchlattice steel roof on steel columns

Purlins fixed across trusses that

support roof covering

sheeting rails

steel columns

lattice steel roof truss

span up to 12.0 m bay 3

to

5 m

Fig. 3.31 presents some practical solutions of industrial buildings with single bay.

Figure 3.31 Industrial Buildings

with single bay: a. Simple stanchion

and truss frame; b. Stanchions with brackets for light

crane gantry and truss frame;c. lattice frame;

d. Battened stanchions with

overhead travelling crane and roof

truss

Lattice beam

Floor Level

Stanchion

Stanchion

Floor Level

Fixed bases at foundation level

Pinned connection

Steel Roof Truss

Sheeting to roof and sides

Steel Roof Truss

Overhead travelling crane

Gantry girders carried on brackets

Floor Level

Pinned base

Sheeting to roof and sides

Gutter

Gutter Gutter

Gutter

Gantry girders

Overhead travelling crane

Roof Truss

Latticed or battened stanchion

Fixed base

Sheeting to roof and sides

a. b.

c.

d.

3.4.2.1. Steel beams

These structural elements are usedfor industrial buildings in thefollowing cases:- Frame beams;-Runway girders for conveyanceand ascension;- Roof purlins;- Wall envelope (girts);- Lintels for doors and windows;- Girders for floor support.

B

D

DxB 203x133 to 914x419

Universal Beam

B

D

DxB 152x152 to 356x406

Universal Column

B

D

DxB 76x38 to 432x102

Channel

A

A

AxA 25x25 to 250x250

Equal Angle

AxB 40x25 to 200x150

Unequal Angle

A

B

AxB 133x102 to 305x457

Structural Tee cut from UB

A

B

D

D 213 to 457

Circular Hollow Section

D

DxD 20x20 to 400x400

Square Hollow Section

D

DB

DxB 50x30 to 450x250Rectangular

Hollow Section

Zed Section Sigma Section Lipped Channel

Figure 3.33 Cold formed sections

Figure.3.32 Rolled and formed sections

3.4.2.2. Steel trusses

Large industrial buildingslike hangars and exhibitionhalls require greater cleardistance between supportsthan can be supplied bybeams and columns framing.

If the clear distance isgreater than can be spannedwith classic rolled beams,several alternatives arerecommended: girders,simple trusses, arches, rigidframes, cantilever-suspension spans or spacestructural systems such asfolded plates, curvilineargrids, thin-shell domes, two-way trusses and cablenetworks [Meritt, 2000].

R

P P P P P

R

a. b.

P P P P P P P P P P

R R R R

PP

P

R R

PP

PP

R R

P

P

PP

PP

P

R RR R

PP

PP

PP

P

c. d.

e. f.

g. h.

j. I.

k.

P P P P

Rv

RH

RH

PRATT

WARREN

FINK

SCISSORS

BOW STRING

VIERENDEEL

R R R R

R R

P PPPPPPP

P

P PP

P PPP PPP

Figure 3.35 Industrial buildingswith truss roofs [Merritt, 2000]

Monitor

Knee brace

Knee brace

Crane

3.4.2.3. Steel columns

Crane steel columns are constructed as bracketed (fig.3.36 a.), stepped(fig.3.36 b.), laced or battened (fig.3.36 c. and d.) columns. Theeccentric crane loads and lateral loads produce important moments inthese types of steel columns. The steel columns in mill buildings andwarehouses are designed to support overhead crane loads.

a. b. c. d.

Figure 3.36 Various types of steel columns

for industrial hallswith crane girders

3.4.2.4. Steel floor deck

The most common type of floor deck used in steel frame structures isconcrete fill on metal deck. The metal deck consists of cold-formedprofiles made of steel sheet, having the yield strength of at least227MPa. The concrete fill must have the 28-day compressive strength ofat least 20 MPa.

Figure 3.37 Cellular steel deck with concrete slab

The corrugate steel sheet carries a double role:- Casing - during execution, it is capable to sustain the self-weight, theweight of concrete and supplementary reinforcement bars, technologicalloads in the casting stage;- Resistance reinforcement situated in the tensile zone, after the concretehardening.

Figure 3.38 Corrugated steel sheets and concrete [P 134-2003]: a. corrugated steel with trapezoidal cross-sections; b. corrugated steel with “omega” cross-sections; c. connectors welded by corrugated steel sheet.

a.

b. c.

Steel frames

Typical beam tocolumn connectionto be considered asshear connections

Clear Span

Tapered columns and rafters give optimum clear span capabilities which keeping unused

interior clearance at a minimum.

Multi Span

The most economical cost per square foot for buildings over 24m wide.

Classic (straight collum)

Straight columns and rafters. This design is common on small width buildings. Easy to

finish the interiors.

High Span

Gives the same design benefits as the Clear Span. Steeper pitch offers more interior

height when required.

Single Slope

Single slope, tapered columns. Especially suited for commercial stores. Offered with interior columns as well.

Single Slope (straight collum)

Single slope, tapered columns. Especially suited for commercial stores. Offered with interior columns as well.

Lean-To

Used to add space at sides or ends. It differs from the slope in that it must be

supported on the high side by an adjoining building column.

Custom Designs

Special framing systems can be provided to meet unusual building

requirements.

The brief was to combine an acoustic barrier with an industrial building-Hessing Cockpit-Netherland

Tubular structure-Hessing Cockpit 2005

Panelized roof systems installed with forklift

Timber structures for industrial buildings

Other materials used for industrial buildings

Brick masonry – industrial hall

Masonry industrial buildings

Masonry industrial buildings