Design of Columns Spreadsheet

Design of Columns Spreadsheet

Columns are classified as short or long depending on their slenderness ratios. Short columns
usually, fail when their materials are overstressed and long columns usually fail due to buckling
which produces secondary moments resulting from the P - D effect.
Columns are classified according to the way they are reinforced into tied and spirally reinforced
columns. Columns are usually reinforced with longitudinal and transverse reinforcement. When
this transverse reinforcement is in the form of ties, the column is called “tied”. If the transverse
reinforcement is in the form of helical hoops, the column is called “spirally reinforced”.
Since the failure of columns often cause extensive damage, they are designed with a higher factor of
safety than beams.

Columns are divided into three types according to the way they are reinforced:
1-Tied Columns
A tied column is a column in which the longitudinal reinforcement bars are
tied together with separate smaller diameter transverse bars (ties) spaced at some interval along
the column height. These ties help to hold the longitudinal reinforcement bars in place during
construction and ensure the stability of these bars against local buckling. The cross sections of such
columns are usually square, rectangular, or circular in shape. A minimum of four bars is used in

rectangular and circular cross-sections.

2-Spirally-Reinforced Columns
They are columns in which the longitudinal bars are arranged in a circle surrounded by a closely
spaced continuous spiral. These columns are usually circular or square in

shape. A minimum of six bars is used for longitudinal reinforcement.

3-Composite Columns
A composite column is a column made of structural steel shapes or pipes surrounded by or filled

by concrete with or without longitudinal reinforcement.

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One Way Slab Design Spreadsheets to Eurocode 2

One Way Slab Design Spreadsheets to Eurocode 2 

Slab consists of two types which are one way slab and two way slabs.
One way slab has two types namely simply supported slab and one way
continuous slab. While two way slabs also consist of two types namely simply
supported two way slab and constrained slab. Slab types can be decided
through side ratio calculation through BS8 110 reference such as:

• Ly / Lx <2.0 (two way)
• Ly / Lx > 2.0 (one-way)

with Ly was longer side and Lx was shorter side.

 A slab is called one-way if the main reinforcement designs within one
direction only. This situation happens if slab is supported only on two sides
only. If slab were supported at all four sides, slab will become one way if
long span ratio (Ly) to short span (Lx) is exceeding 2. Because of slab string
one-way then reinforcement in span direction is main reinforcement, while
reinforcement in direction perpendicular by span known as second
reinforcement which functions as binding main reinforcement and help stress
distribution because of temperature changes and concrete shrinkage.

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Design Laterally Loaded Elastic Piles Spreadsheet

Design Laterally Loaded Elastic Piles Spreadsheet

Understanding and mastering the seismic analysis and design of deep foundations is a challenging yet essential element of the advanced education of students in the field of civil engineering. Our past experience in the academic context of helping students achieve the desired outcomes had been a frustrating endeavor, given the time and effort invested. It is in part in response the need to provide a leaner and more efficient learning and teaching approach that the work described in this paper evolved. In essence, the transfer of lateral loads from deep foundations to the subsurface strata is a complex soil-structure interaction problem. The movements and flexural stresses in the pile depend on the soil resistance, while the soil resistance is a function of the deformations of the pile itself. Furthermore, the ultimate resistance of a vertical pile to a lateral load and the deflection of the pile as the load builds up to its ultimate value are complex and involve the interaction between a semi-rigid structural element and soils which deforms partly elastically and partly plastically. Given the typically limited time and resources allocated to this topic in a three credit course, as other equally relevant applications are to be covered, imparting sufficient and fundamental understanding of this applied problem constitutes a real challenge that the spreadsheet approach presented herein attempted to meet.

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Prestressed Composite Section Design

Prestressed Composite Section Design

The design of a composite section depends upon the type of composite section, the
stages of prestressing, the type of construction and the loads. The type of construction
refers to whether the precast member is propped or unpropped during the casting of
the CIP portion. If the precast member is supported by props along its length during the
casting, it is considered to be propped. Else, if the precast member is supported only at
the ends during the casting, it is considered to be unpropped.

The advantages of composite construction are as follows.
1) Savings in formwork
2) Fast-track construction

3) Easy to connect the members and achieve continuity.

The prestressing of composite sections can be done in stages. The precast member
can be first pre-tensioned or post-tensioned at the casting site. After the cast-in-place
(cast-in-situ) concrete achieves strength, the section is further post-tensioned.
The grades of concrete for the precast member and the cast-in-place portion may be
different. In such a case, a transformed section is used to analyse the composite

section.

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Steel Connection Design Spreadsheet

Steel Connection Design Spreadsheet

Steel Connection is divided into two common methods: bolting and welding.
Bolting is the preferred method of Steel connecting members on the site. Staggered bolt layout allows easier access for tightening with a pneumatic wrench when a connection is all bolted.  High strength bolts may be snug-tightened or slip-critical. Snug-tightened connections are referred to as bearing connections Bolts in a slip-critical connection act like clamps holding the plies of the material together.Bearing type connections may have threads included ( Type N ) or excluded ( Type X ) from the shear plane(s).  Including the threads in the shear plane reduces the strength of the connection by approximately 25%.  Loading along the length of the bolt puts the bolt in axial tension. If tension failure occurs, it usually takes place in the threaded section.Three types of high strength bolts A325, A490 (Hexagonal Head Bolts), and F1852 (Button Head Bolt). A325 may be galvanized A490 bolts must not be galvanized F1852 bolts are mechanically galvanized. High strength bolts are most commonly available in 5/8” – 1 ½” diameters. Bolting requires punching or drilling of holes. Holes may be standard size holes, oversize holes, short slotted holes, long slotted holes

 Due to high costs of labor, extensive field -welding is the most expensive component in a steel frame. Welding should be performed on bare metal. Shop welding is preferred over field welding. The weld material should have a higher strength than the pieces being connected.Single-pass welds are more economical than multi-pass welds. The most economical size weld that may be horizontally deposited in one pass has 5/16”. Fillet welds and groove welds make up the majority of all structural welds. The strength of a fillet weld is directly proportional to the weld’s throat dimension. The capacity of a weld depends on the weld’s throat dimension and its length.

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Staircase Analysis and Design Spreadsheet

Staircase Analysis and Design Spreadsheet

Staircases provide means of movement from one floor to another in a structure. Staircases
consist of a number of steps with landings at suitable intervals to provide comfort and safety
for the users.

Types of Stairs
For purpose of design, stairs are classified into two types; transversely, and longitudinally
supported.
a- Transversely supported (transverse to the direction of movement):
Transversely supported stairs include:
§ Simply supported steps supported by two walls or beams or a combination of both.
§ Steps cantilevering from a wall or a beam.
§ Stairs cantilevering from a central spine beam.
b- Longitudinally supported (in the direction of movement):
These stairs span between supports at the top and bottom of a flight and unsupported at the
sides. Longitudinally supported stairs may be supported in any of the following manners:
a. Beams or walls at the outside edges of the landings.
b. Internal beams at the ends of the flight in addition to beams or walls at the outside edges of
the landings.
c. Landings which are supported by beams or walls running in the longitudinal direction.
d. A combination of (a) or (b), and (c).

e. Stairs with quarter landings associated with open-well stairs.

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Beam Analysis Spreadsheet

Beam Analysis Spreadsheet

The "BeamAnal" calculates Shear Force, Bending Moment and Deflection at 31 positions along the member length. Member Lengths can be a single span simply supported or a 2, 3 or 4 span continuous over middle supports. The analysis results are produced in a tabular form and are also plotted in 3 graphs for rapid comprehension.
The program uses usual equations for Shear Force, Bending Moment and Deflection equations along the member span. When middle supports are specified, simultaneous equations are set up and solved to calculate the middle support reactions.

The program internally works in consistent Force and Length Units. To help comprehend results, use of mixed units is allowed. Inertia and elastic modulus of the member section can therefore be defined in any units. Similarly, any desired units can be set deflection values. To specify units, go to the Units sheet and describe your own units of Force, Distance, Inertia, Modulus and Deflection. You need to calculate and specify conversion factors from consistent units to your chosen mixed units. Sample values are given for your guidance in this sheet. The units cannot however be mixed in one project file. Chosen units apply to all beams in the file. This means that if units are changed in the middle of building up a data file, beam properties for all beams need to be re-defined to match the chosen units.

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Design of Bridge Slab Spreadsheet

Design of Bridge Slab Spreadsheet

Reinforced Slab Bridges used For short spans, a solid reinforced concrete slab, generally cast in-situ rather than precast, is the simplest design to about 25m span, such voided slabs are more economical than prestressed slabs. Slab bridges are defined as structures where the deck slab also serves as the main load-carrying component. The span-to-width ratios are such that these bridges may be designed for simple 1-way bending as opposed to 2-way plate bending. This design guide provides a basic procedural outline for the design of slab bridges using the LRFD Code and also includes a worked example.
The LRFD design process for slab bridges is similar to the LFD design process. Both codes require the main reinforcement to be designed for Strength, Fatigue, Control of Cracking, and Limits of Reinforcement. All reinforcement shall be fully developed at the point of necessity. The minimum slab depth guidelines specified in Table 2.5.2.6.3-1 need not be followed if the reinforcement meets these requirements.
For design, the Approximate Elastic or “Strip” Method for slab bridges found in Article 4.6.2.3 shall be used.
According to Article 9.7.1.4, edges of slabs shall either be strengthened or be supported by an edge beam which is integral with the slab. As depicted in Figure 3.2.11-1 of the Bridge Manual, the #5 d1 bars which extend from the 34 in. F-Shape barrier into the slab qualify as shear reinforcement (strengthening) for the outside edges of slabs. When a 34 in. or 42 in. F-Shape barrier (with similar d1 bars) is used on a slab bridge, its structural adequacy as an edge beam should typically only need to be verified. The barrier should not be considered structural. Edge beam design is required for bridges with open joints and possibly at stage construction lines. If the out-to-out width of a slab bridge exceeds 45 ft., an open longitudinal joint is required.

Design of Bridge Slab Spreadsheet

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Beam Column Design Spreadsheet to ACI-318 and ACI-350

Beam Column Design Spreadsheet to ACI-318 and ACI-350

Beam column design spreadsheet evaluates concrete members carrying both flexure and axial load using thrust-moment, or P-M, interaction diagrams generated per ACI 318 and ACI 350. Standard axial/flexural provisions, Ch 10, are considered.  ACI 350 durability factor is used to factor down the flexural and axial capacities instead of factoring up the factored loads. The end result is an "inner curve" that governs for ACI 350 capacity in the tension-controlled and transition zones.

Assumptions/Limitations:

- Only one layer of steel each for top face reinforcing and bottom face reinforcing

- Ties are provided for confinement (not spirals)

Validation:

-XLC formulae and peer review provide verification of intended functionality.

-Cross-check against software solution (SP Column)

References:

-ACI 318-11

-ACI 350-06

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Excel Construction Management Templates

Excel Construction Management Templates

Excel Construction Management Templates are very important for managers as it's
very difficulit to manage construction projects. they Require alot of 
stakeholders, details and documentation. So we provide more
 than 15 free excel construction management templates to download and use them
the templates involve : 

• Construction Timeline
• Construction Budget
• Construction Estimator
• Bid Tabulation Template
• Abstract of Bids Template
• Subcontractor Documentation Tracker
• Construction Documentation Tracker
• Daily/Weekly Inspection Report
• Contractor Progress Payment Template
• Change Order Request Summary
• Change Order Log
• Request for Information Log
• Residential Remodel Project Timeline
• Certified Wage & Hour Payroll Form
• Time & Materials Invoice
• Project Punchlist
• Project Closeout Checklist
• Construction Management with Smartsheet

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Ribbed Slab Design Spreadsheets to Eurocode

Ribbed Slab Design Spreadsheets to Eurocode

• Ribbed slabs are widely used in many countries. This is attributed to the rapid shattering, ease of construction, and the reduction in the time of erection. This type of slabs or flooring system consists of series of small closed spaced reinforced concrete T-beams. These floors are suitable for building with light live loads.
The advantages of ribbed slab :

• Quick and simple to install
• Minimizes the need for skilled labor
•  Supplied on short lead times
•  Tailored to any type of site requirements
•  Saves aggregate, concrete and steel
•  Speeds construction
•  Lowering building costs
•  Reducing the cycle time of building
•  Maximum control of concrete curing
• Providing a higher quality floor surface;
• Achieving longer spans in pile/beam structural
• slabs and pile numbers may be optimized to limit additional costs
•  Monolithic poured concrete foundation slabs
•  Solution for Structural Weight Limits
• Contributing to GREEN or LEED certified building

In one-way ribbed slab, loads are transferred in one direction, and the main reinforcement is distributed in the same direction of the load. With accurate to temperature and shrinkage,

 minimum of Φ33 bars diameter will be used in both direction and 
crossing each other over the blocks ( practically).I

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Two Way Slab Design Spreadsheets to Eurocode 2

Two Way Slab Design Spreadsheets to Eurocode 2 

Two-way spanning slabs For rectangular slabs with standard edge conditions and subject to uniformly distributed loads, normally the bending moments are obtained using tabulated coefficients. Such
coefficients are provided later in this section.
 Main reinforcement for two way slabs designs in both directions.
This situation happen when slab were supported at all four span sides and
ratio long per short span less or equivalent to two. Bending moment and shear
force for two way slab depends on ratio ly / lx and extension between his slab
and supporter whether easily supported or constrained.Two way simply supported slab
 have a panel and easily
supported in edge and panel can lift upward when moment acting on
it, slab is supported by beam steel or extension between slab and non

monolithic beam. Moment only exist in center part of span.

Two way slab constrained have more than one panel or in
section slab edge can be prevent from lifted. This situation happen
when slab connected by monolithic with the supporter or slab panel
connected by monolithic between one and another and moment acting
at slab edge. This type of slab has four moment value at one slab
panel namely two moment amid span and two moment at direction x and y.

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Shear Strengthening of T-beam with FRP

Shear Strengthening of T-beam with FRP

The rehabilitation of existing reinforced concrete (RC) bridges and building becomes necessary due to ageing, corrosion of steel reinforcement, defects in construction/design, demand in the increased service loads, and damage in case of seismic events and improvement in the design guidelines. Fiber-reinforced polymers (FRP) have emerged as promising material for rehabilitation of existing reinforced concrete structures. The rehabilitation of structures can be in the form of strengthening, repairing or retrofitting for seismic deficiencies. RC T-section is the most common shape of beams and girders in buildings and bridges. Shear failure of RC T-beams is identified as the most disastrous failure mode as it does not give any advance warning before failure. The shear strengthening of RC T-beams using externally bonded (EB) FRP composites has become a popular structural strengthening technique, due to the well-known advantages of FRP composites such as their high strength-to-weight ratio and excellent corrosion resistance.

A few studies on shear strengthening of RC T-beams using externally bonded FRP sheets have been carried out but still the shear performance of FRP strengthened beams has not been fully understood. The present study therefore explores the prospect of strengthening structurally deficient T-beams by using an externally bonded fiber reinforced polymer (FRP).
This study assimilates the experimental works of glass fiber reinforced polymer (GFRP) retrofitted RC T-beams under symmetrical four-point static loading system. The thirteen number of beams were of the following configurations, (i) one number of beam was considered as the control beam, (ii) seven number of the beams were strengthened with different configurations and orientations of GFRP sheets, (iii) three number of the beams strengthened by GFRP with steel bolt-plate, and (iv) two number of beams with web openings strengthened by U-wrap in the shear zone of the beams.
The first beam, designated as control beam failed in shear. The failures of strengthened beams are initiated with the debonding failure of FRP sheets followed by brittle shear failure. However, the shear capacity of these beams has increased as compared to the control beam which can be further improved if the debonding failure is prevented. An innovative method of anchorage technique has been used to prevent these premature failures, which as a result ensure full utilization of the strength of FRP. A theoretical study has also been carried out to support few of the experimental findings.

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Core Wall Design Spreadsheets to Eurocode 2

Core Wall Design Spreadsheets to Eurocode 2

 core-walls  have been the most popular seismic force resisting system in western Canada
for many decades, and recently have become popular on the west coast of the US for high-rise buildings up to
600 ft (180 m) high. Without the moment frames that have traditionally been used in high-rise concrete
construction in the US, the system offers the advantages of lower cost and more flexible architecture. In the US,
such buildings are currently being designed using nonlinear response history analysis (NLRHA) at the
Maximum Considered Earthquake (MCE) level of ground motion. In Canada, these buildings are designed
using only linear dynamic (response spectrum) analysis at the MCE hazard level combined with various
prescriptive design procedures. This paper presents the background to some of the prescriptive design
procedures that have recently been developed to permit the safe design of high-rise core-wall buildings using
only the results of response spectrum analysis (RSA).

The series of European standards commonly known as “Eurocodes”, EN 1992 (Eurocode 2, in the
following also listed as EC2) deals with the design of reinforced concrete structures – buildings,
bridges and other civil engineering works. EC2 allows the calculation of action effects and of
resistances of concrete structures submitted to specific actions and contains all the prescriptions and
good practices for properly detailing the reinforcement.

In this spreadsheet , the principles of Eurocode 2, part 1-1 are applied to the design of core wall. 

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Punching Shear Strength Design of RC Slab According ACI318M-08

Punching Shear Strength Design of RC Slab According ACI318M-08

The main objective of this sheet is to evaluate the effect of design tje RC slab for punching shear strength . The increasing of the punching shear strength and deformation capacity
 when subjected to patch load was studied here.
An experimental study was carried out on reinforced concrete slabs under a central patch load with
circular, square and rectangular shapes of patch areas. A single concrete mix design was used
throughout the test program. All of slab specimens were reinforced with distributed mesh
reinforcement with equal steel ratios in both directions. The validation of the experimental work
was made by analyzing the tested slabs by finite element method under cracking load. The results
obtained by the finite element method were found to compare well with those obtained
experimentally. In order to calculate the ductility for the tested slabs, the punching load has been
determined by applying the published failure criterion and a load-rotation relationship obtained
from semi-empirical relationship for the tested slabs. Conclusions on the influence of patch area on
the punching shear capacity of reinforced concrete slabs were drawn. The experimental results
confirm that the strength and deformation capacity are slightly influenced by the shape of the patch
area. Among all specimens, the slabs with circular shape of patch area exhibited the best
performance in terms of ductility and splitting failure.

In flat-plate floors, slab-column connections are subjected to high shear stresses produced by the transfer of the internal forces between the columns and the slabs (ACI-421.1R-08, 2008; ACI-421.1-99, 1999). Normally it is desired to increase the slab thickness or using drop panels or column capitals of exceptionally high strength for shear in reinforced concrete slab around the supporting column. Occasionally, methods to increase punching shear resistance without modifying the slab thickness are often preferred (Cheng and Montesinos, 2010). The ways to transfer the force from column to the slab need to be studied to increase the shear resistance. Several reinforcement alternatives for increasing punching shear resistance of slab-column connections, including bent-up bars (Hawkins et al., 1974; Islam and Park, 1976), closed stirrups (Islam and Park, 1976), shearheads (Corley and Hawkins, 1968), and shear studs (Dilger and Ghali, 1981), have been evaluated in the past five decades. But there is a little experimental and theoretical information about the influence of patch area or cross section area shape for supporting column in the reinforced concrete shear resistance.

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Canadian Seismic Design of Steel Structures

Canadian Seismic Design of Steel Structures

Design of Steel Structures of the Canadian Standards Association (CSA) governs the design of the majority of steel structures in Canada. Clause 27 of the standard includes the earthquake design provisions for seismic force resisting systems for which ductile seismic response is expected. Technical changes and new requirements have been incorporated in the 2009 edition of CSA S16, including modifications of the expected material properties for HSS members, consideration of protected zones, definitions of brace probable compressive and tensile resistances for capacity design and special requirements for braces intersecting columns between floors for concentrically braced steel frames, new seismic provisions for buckling restrained braced steel frames, design and detailing requirements for built-up tubular ductile links in eccentrically braced steel frames, changes to the requirements for ductile steel plate walls and for plate walls with limited ductility, including allowances for perforations and corner cut-outs in infill plates, and special provisions for steel frames of the Conventional Construction category above 15 m in height. These modifications were developed in parallel with the 2010 National Building Code of Canada (NBCC). The paper summarizes the new CSA S16-09 seismic design requirements with reference to NBCC 2010.

Basic capacity design provisions are given in CSA S16 to ascertain that minimum strength hierarchy exists along the lateral load path such that the intended ductile energy dissipation mechanism is mobilized and the integrity of the structure is maintained under strong ground shaking. In the design process, the yielding components of the SFRS may be oversized compared to the specified design seismic forces, as would be the case when drift limits, minimum member sizes or non-seismic load combinations govern the design. In this case, it is specified both in NBCC 2010 and CSA S16 that the design forces in capacity-protected elements need not exceed those induced by a storey shear determined with RoRd = 1.3. This upper bound essentially corresponds to the elastic seismic force demand reduced by 1.3, recognizing that nonyielding components will likely possess minimum overstrength. This 1.3 reduction factor only applies if the governing failure mode is ductile, and RoRd = 1.0 must be used otherwise.

This file contains formatted spreadsheets to perform the following calculations:
 - Section 1: Area of equivalent diagonal brace for plate wall analysis (Walls).
 - Section 2: Design of link in eccentrically braced frames (EBF).
 - Section 3: Design of Bolted Unstiffened End Plate Connection (BUEP).
 - Section 4: Design of Bolted Stiffened End Plate Connection (BSEP).
 - Section 5: Design of Reduced Beam Section Connection (RBS).
 - Section 6: Force reduction factor for friction-damped systems (Rd_friction).

 Additionally, this file contains the following tables:
 - Valid beam sections for moment-resisting connections (B_sections).
 - Valid column sections for moment-resisting connections (C_sections).
 - Valid bolt types for moment-resisting connections (Bolts).
 - Database of properties of all sections (Sections Table).

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Retaining Wall with Anchors Analysis and Design Spreadsheet

Retaining Wall with Anchors Analysis and Design Spreadsheet

This spreadsheet provides the design and analysis of retaining wall with anchors.
Retaining walls with anchors shall be dimensioned to ensure that the total lateral
load, Ptotal, plus any additional horizontal loads, are resisted by the horizontal component
of the anchor Factored Design Load Thi, of all the anchors and the reaction, R, at or below
the bottom of the wall. The embedded vertical elements shall ensure stability and sufficient
passive resistance against translation. The calculated embedment length shall be the greater
of that calculated by the Designer or Geotechnical Services.

Typical design steps for retaining walls with ground anchors are as follows:

Step 1 : Establish project requirements including all geometry, external loading conditions
(temporary and/ or permanent, seismic, etc.), performance criteria, and construction
constraints. Consult with Geotechnical Services for the requirements.

Step 2 : Evaluate site subsurface conditions and relevant properties of the in situ soil or
rock; and any specifications controlled fill materials including all materials strength
parameters, ground water levels, etc. This step is to be performed by Geotechnical Services.

Step 3 : Evaluate material engineering properties, establish design load and resistance
factors, and select level of corrosion protection. Consult with Geotechnical
Services for soil and rock engineering properties and design issues.

Step 4 : Consult with Geotechnical Services to select the lateral earth pressure distribution
acting on back of wall for final wall height. Add appropriate water, surcharge, and
seismic pressures to evaluate total lateral pressure. Check stability at intermediate
steps during contruction. Geotechnical numerical analysis may be required to
simulate staged construction. Consult Geotechnical Services for the task, should it be required.

Step 5 : Space the anchors vertically and horizontally based upon wall type and wall height.
Calculate individual anchor loads. Revise anchor spacing and geometry if necessary.

Step 6 : Determine required anchor inclination and horizontal angle based on right-of-way
limitations, location of appropriate anchoring strata, and location of underground structures.

Step 7 : Resolve each horizontal anchor load into a vertical force component and a force
along the anchor.

Step 8 : Structure Design checks the internal stability and Geotechnical Services checks the
external stability of anchored system. Revise ground anchor geometry if necessary.

Step 9 : When adjacent structures are sensitive to movements Structure Design and
Geotechical Services shall jointly decide the appropriate level and method of
analysis required. Revise design if necessary. For the estimate of lateral wall
movements and ground surface settlements, geotechnical numerical analysis is
most likely required. Consult with Geotechnical Services for the task, should it be required.

Step 10 : Structure Design analyzes lateral capacity of pile section below excavation subgrade.
Geotechnical Services analyzes vertical capacity. Revise pile section if necessary.

Step 11 : Design connection details, concrete facing, lagging, walers, drainage systems, etc.
Consult with Geotechnical Services for the design of additional drainage needs.


Step 12 : Design the wall facing architectural treatment as required by the Architect.

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Footing Design of Shear Wall Based on ACI 318-14

Footing Design of Shear Wall Based on ACI 318-14

The criterion for the design of foundations of earthquake resisting
structures is that the foundation system should be capable of supporting the
design gravity loads while maintaining the chosen seismic energy dissipating
mechanisms of the structure. The foundation system in this context includes
the foundation structure, consisting of reinforced concrete construction, piles,
caissons and the supporting soil.

It is evident that for this criterion a suitable foundation system for a given
superstructure can be conceived only if the mechanisms by which earthquake actions
are disposed of are clearly defined. In most structures inelastic deformations
during large earthquakes are expected. Consequently for these
structures provisions are to be made for energy dissipation, usually by flexural
yielding. It is vital that energy dissipation be assigned by the designer
to areas within the superstructure or within the foundation structure in such
a manner that the expected ductility demands will remain within recognized
capabilities of the selected components. It is particularly important to ensure that
any damage that might result in the foundation structure does not lead to a
reduction of strength that might affect gravity load carrying capacity.

After defining design criteria in general for foundations
of earthquake resisting reinforced concrete structures, principles
are set out which govern the choice of suitable foundation systems
for various types of shear wall structures. The choice of
foundation systems depends on whether the seismic response of the
superstructure during the largest expected earthquake is to be elastic
or inelastic. For inelastically responding superstructures, preferably
the foundation system should be designed to remain elastic.
For elastically responding superstructures, suitable foundation systems
may be energy dissipating, elastic or of the rocking type. Design

criteria for each of these three foundation types are suggested.

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RC Element Analysis and Design Program

RC Element Analysis and Design Program

The theory and techniques relative to the design and
proportioning of concrete mixes, as well as the placing,
finishing, and curing of concrete, are outside the scope
of this book and are adequately discussed in many other
publications . Field testing, quality control, and inspec-
tion are also adequately covered elsewhere. This is not to
imply that these are of less importance in overall concrete
construction technology but only to reiterate that the objec-
tive of this book is to deal with the design and analysis of
reinforced concrete members.

The design and construction of reinforced concrete build-
ings is controlled by the Building Code Requirements for

Structural Concrete (ACI 318-11) of the American Concrete
Institute (ACI) [1]. The use of the term code in this text
refers to the ACI Code unless otherwise stipulated. The
code is revised, updated, and reissued on a 3-year cycle. The
code itself has no legal status. It has been incorporated into
the building codes of almost all states and municipalities
throughout the United States, however. When so incorpo-
rated, it has official sanction, becomes a legal document, and
is part of the law controlling reinforced concrete design and

construction in a particular area.

therefore, tensile reinforcement must be embedded
in the concrete to overcome this deficiency. In the United
States, this reinforcement is in the form of steel reinforcing
bars or welded wire reinforcing composed of steel wire. In
addition, reinforcing in the form of structural steel shapes,
steel pipe, steel tubing, and high-strength steel tendons is

permitted by the ACI Code.

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DESIGN OF COMPOSITE BEAM-COLUMNS

 DESIGN OF COMPOSITE BEAM-COLUMNS

The design of composite columns is seamlessly integrated within the
program. Initiation of the design process, along with control of various design
parameters, is accomplished using the Design menu. Automated design at the
object level is available for any one of a number of user-selected design codes,
as long as the structures have first been modeled and analyzed by the program.
Model and analysis data, such as material properties and member forces, are
recovered directly from the model database and are used in the design process
in accordance with the user defined or default design settings. As with all
design applications, the user should carefully review all of the user options and
default settings to ensure that the design process is consistent with the user’s
expectations. Composite column design options include the
use of the Direct Analysis Method. The software is well suited to make use of
the Direct Analysis Method because it can capture the second-order P-Δ and P-
δ effects, provided the user specifies that a nonlinear P-Δ analysis is performed.

For each design combination, composite column members are checked at a
number of locations (stations) along the length of the object. The stations are
located at equally spaced segments along the clear length of the object. By
default, at least three stations will be located in a column or brace member. The
user can overwrite the number of stations in an object before the analysis is run
and refine the design along the length of a member by requesting more
stations. Refer to the program Help for more information about specifying the

number of stations in an object.

The code requires that stability shall be provided for the structure as a whole
and for each of the elements. Any method of analysis that considers the influence
of second order effects of P-Δ and P-δ , geometric imperfections, out-ofplumbness,

and member stiffness reduction due to residual stresses are permitted by the code. The effects of geometric imperfection and out-of-plumbness
generally are captured by the use of notional loads. The effect of axial, shear
and flexural deformations and the effects of residual stresses on the member
stiffness reduction has been considered in a specialized method called “Direct
Analysis Method.” This method can come in different incarnations (formats)
according to the choice of the engineer as allowed in the code.

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