Nomenclature and Printout Explanation
Bridge Layout
Setting | Description |
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Overall width | Overall width of the bridge. |
Left Curb/Right Curb | Width of the left and right curbs. |
Curb-to-curb width | Overall width minus curb widths. |
Number of spans | Total number of spans. |
Number of lanes | Total number of lanes. |
Lane width | Width of each lane. |
Topping Thickness | Concrete thickness of deck. |
Suppl. Thickness | Thickness of supplemental concrete layer added on top of the deck. |
Haunch Thickness | Thickness of build up over each beam flange. |
Haunch Width | Width of build up over each beam flange. |
Concrete Properties
Setting | Description |
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C.I.P | Cast-in-place topping. |
fck | 28-day compressive strength of concrete. |
Wc | Weight of concrete. |
Ec | Modulus of elasticity of 28-day strength concrete. |
f'ci | Compressive strength of concrete at release of prestress. |
Eci | Modulus of elasticity of concrete at release. |
Span Data
Setting | Description |
---|---|
Span | Span number. |
Pier-to-pier | Centerline of pier to centerline of pier. |
Precast | Precast beam length. |
Brg-to-brg | Centerline of bearing to centerline of bearing at final conditions. |
Pier CL-Precast | Distance from centerline of left pier to left end of precast beam. |
Release | Distance between centerlines of temporary supports at release. |
Bridge c/s M.I. | Moment of inertia of the entire composite bridge cross-section. |
Beam Data
Setting | Description |
---|---|
Span | Span for which the data is listed in the particular section. |
No. | Beam line number. |
ID | Beam identification. |
Loc-prev | The distance to the centerline of a particular beam measured from the centerline of the previous beam to its left. For the first beam in a span, it is the distance between its centerline and the leftmost edge of bridge cross-section. |
Area | Gross area of cross-section of precast girder. |
M.I. | Gross moment of inertia of girder cross-section. |
Height | Height of the girder. |
Yb | Distance from bottom of girder to its center of gravity. |
B-Topg | Width of precast top flange. |
B-Trib | Tributary width over which loads will be calculated for design purposes. |
Loads on Precast
Superimposed dead loads on precast beams.
Setting | Description |
---|---|
Span | Span number. |
Beam | Beam number. |
Type | Load type, e.g., line load or point load. |
Mag | Magnitude of line load or point load. |
Loc | Location of point load measured from left bearing. |
Diaphragm Loads
Superimposed dead loads of diaphragms on the precast beams.
Setting | Description |
---|---|
Span | Span number. |
Beam | Beam number. |
Mag | Magnitude of concentrated diaphragm load. |
Loc | Location of point load measured from left bearing. |
Loads on Composite
Superimposed dead loads on the composite section.
Setting | Description |
---|---|
Span | Span number. |
Type | Load type, e.g., area load, line load,trapezoidal or point load. |
Mag | Magnitude of area load, line load, trapezoidal or point load. |
Loc | Location of point load measured from the left pier centerline. |
Width | Width of area load. |
Mag.2, Loc.2 | Ending Location and Magnitude for trapezoidal load. |
Precast Data
Setting | Description |
---|---|
Section ID | Girder identification. |
Type | Type of the girder. |
Flng width: Top, Bot | Top and bottom flange width of specified girder. |
Flng thick: Top, Bot | Thickness of top and bottom flanges of the specified girder. |
Stems: No | Number of stems of girder cross-section. |
Top | Stem width at its top. |
Bot | Stem width at its bottom. |
Shear width | Number of stems times average stem width. |
General Bridge Data
Setting | Description |
---|---|
Bridge width | Overall bridge width. |
Curb-to-curb | Bridge width minus curb widths. |
Beam Spac. Lt/Rt | Beam spacing. Distance from centerline of beam on left, Lt, and distance from centerline of beam on right, Rt. |
Lane Width | Design lane width. |
No. of lanes | Number of lanes across the bridge width. |
Interior/Exterior | Indicates if the beam is considered as exterior or interior beam for the purpose of calculating the live load distribution factor. |
Skew Angle | For skewed bridges, angle measured from centerline of pier to the normal to bridge centerline. |
Topping Data
Setting | Description | ||||||||
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Deck Thickness | Concrete thickness of deck. | ||||||||
Haunch | Thickness of build-up over the beam flange.
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General Load Data
Setting | Description | ||||||||
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Dead Loads on Precast | Dead loads applied to the precast girder.
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Diaphragm Loads |
Dead loads of diaphragms applied as point loads to the precastgirder.
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Dead Load on Composite | See Loads on Composite. | ||||||||
Impact | Impact factor per IRC:6-2000, clause 211.2. | ||||||||
G | Dead load on precast. | ||||||||
SG | Superimposed dead load on composite. |
Load Factors
Setting | Description |
---|---|
Load Factors, G | For dead loads on precast. |
Load Factors, SG | For superimposed dead loads. |
Load Factors, QIm | For live loads. |
General Span Data
Setting | Description |
---|---|
Overall Length | Overall length of precast girder. |
Release Length | Distance between temporary supports at release. |
Design Length | Bearing to bearing distance between girder supports at final. |
Miscellaneous
Setting | Description |
---|---|
Kern pts | Upper and lower kern points of the cross-section measured from the bottom of the beam. |
Trans len mult | Transfer length multipliers for bonded and debonded prestressing strands. |
Dev len mult | Development length multipliers for bonded and debonded prestressing strands. |
Distribution/Reaction Factors
Setting | Description | ||||
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Dead Load | SG/Composite dead load distribution factor (computed or manual). | ||||
Live Load - Girder |
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Pedestrian | Pedestrian load distribution factor (same as dead load DF). | ||||
Computed or Manual | Specifies whether the values were calculated by the program or user-defined. |
Section Properties
Setting | Description | ||||||||||
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Precast | Section properties of precast beam alone. | ||||||||||
Composite | Section properties of precast beam plus topping. Same as Precast if no topping is used. | ||||||||||
Area | Area of Precast/Composite. | ||||||||||
Total Height | Total height of Precast/Composite. | ||||||||||
*(Asterisk) | Indicates where ratio of Ect/Ec is used for calculation of section properties for Composite. | ||||||||||
Mom of Inertia | Moment of inertia about center of gravity of Precast/Composite. | ||||||||||
Ht. of c.g. | Height of center of gravity of Precast/Composite measured from the bottom of the precast. | ||||||||||
Density | Density of concrete. | ||||||||||
Self-weight | Self-weight of Precast/Composite. | ||||||||||
At 28-Days | Strength, stresses, and elasticity of concrete at 28-days.
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At Release |
Strength, stresses, and elasticity of PRECAST/COMPOSITE/SUPPLEMENTAL at release.
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Use transformed strands and rebar | No" means strand and rebar is not transformed into concrete properties. "Yes" means strand and rebar are transformed into concrete section properties. An area and height of rebar to be transformed can be specified. |
Prestressed Steel
Setting | Description |
---|---|
Prestressed Steel | Information about prestressing strands. |
End Pattern | Location of strands at the end of the beam. |
Ycg | Center of gravity of strands measured from the bottom of the precast. |
Mid Pattern | Location of strands at the middle of the beam. |
Ycg | Center of gravity of strands measured from the bottom of the precast. |
Strand Dia | Diameter of one prestressing strand. |
Strand Area | Area of one prestressing strand. |
Total strand area | Total area of strands. |
Trans. len, basic | Basic transfer length. |
Trans. len, bonded | Transfer length for bonded strands. |
Trans. len, debonded | Transfer length for debonded strands. |
Ult. strength | Ultimate strength of prestressing strands, f's. |
Initial prestress | Jacking stress as a fraction of ultimate strength. |
Initial pull | Initial prestress times total strand area. |
Dev len, basic | Basic development length ). |
Dev len, bonded | Development length for bonded strands. |
Dev len, debonded | Development length for debonded strands. |
Hold down force | Vertical component of draped strands force. |
Beam shortening | Computed as PL/AE. |
Reinforcing Steel
Setting | Description |
---|---|
Tension steel | Characteristics of tension reinforcement steel. |
fy | Specified yield strength of tension reinforcement. |
fs | Tensile stress in tension reinforcement. |
Shear steel | Characteristics of steel for shear reinforcement. |
fsy | Specified yield strength of shear reinforcement. |
Modulus of elasticity | Modulus of elasticity of tension and shear steel. |
Prestress Losses
Setting | Description | ||||||||||
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Midspan |
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Age of Loading | Age of loading. | ||||||||||
Es | Modulus of elasticity of prestressing steel strand. | ||||||||||
Eci | Modulus of elasticity of concrete, at release. | ||||||||||
IRC LOSSES | Loss of prestress by IS: 1343-1980. | ||||||||||
Release | Loss of prestress at release. | ||||||||||
Final | Final loss of prestress. | ||||||||||
Steel relaxation RET CRs | Loss due to relaxation of prestressing steel. | ||||||||||
Elastic shortening ES | Loss of prestress due to elastic shortening. | ||||||||||
Strain Shrinkage | Strain Shrinkage. | ||||||||||
Concrete shrinkage, SH | Loss of prestress due to concrete shrinkage. | ||||||||||
Concrete creep, CRc | Loss of prestress due to creep of concrete. | ||||||||||
Strain Shrinkage | Strain Shrinkage. | ||||||||||
Total | Total loss of prestress at release/final. |
Shielding and Reduced Initial Pulls
Setting | Description |
---|---|
Group | Number of a group composed of one or two strands. |
Strands | Number of strands in a specified group. |
Heights/End | Location of center of gravity of the group of strands at both ends of the precast. |
Heights/Mid | Location of center of gravity of the group of strands at the midspan. |
Shielding/End | Length of shielding at midspan. Shielding extends half the specified length on each side of midspan. |
Shielding/Mid |
Length of shielding at midspan. Shielding extends half the specified length on each side of midspan. |
Initial Pull Frac | Initial pull fraction of strands represented as a fraction of ultimate strength of prestressing steel. |
Initial Pull/Str. | Initial prestress force per strand. |
Shear and Moment Envelope
Setting | Description |
---|---|
M | Maximum moment due to a particular load component at a section. |
V | Corresponding shear associated with the above moment. This is the maximum absolute value for shear. |
M+ | Maximum positive moment due to live load, pedestrian load, or combined total maximum positive moment. |
V | Shear corresponding to M+. This is the maximum absolute value for shear. |
M- | Maximum negative moment due to live load, pedestrian load, or combined total maximum negative moment. |
V | Shear corresponding to M-. This is the maximum absolute value for shear. |
Vmax | Maximum absolute value of shear due to live load, pedestrian load, or combined total absolute maximum shear. |
M | Moment corresponding to Vmax. |
Bearing | Left and right bearing centerlines. |
Trans | Transfer location of strands taken as fifty strand diameters from the end of the precast and measured from the centerline of bearing. |
H/2 | Half of the overall depth of the member measured from the inner face of the bearing pad. |
0.xL | Point of 0.x of precast length measured from the left bearing. |
Midspan | Midspan of the girder. |
Self wt. | M and V due to self-weight of precast calculated for simply supported beam with "brg-to-brg" span length. Includes gamma factors. |
G-Prec |
M and V due to dead load acting on bare precast calculated for simply supported beam with brg-to-brg span length. |
Deck + Haunch | M and V due to deck and haunch weight acting on precast calculated for simply supported beam with "brg-to-brg" span length. Includes gamma and beta factors. |
SG-Comp |
M and V due to superimposed dead loads acting on composite. Calculated for continuous beam model with pier-to-pier spans. |
QIm | M and V envelopes due to selected live loads. Includes impact factors. |
Pedestrian | M and V envelopes due to pedestrian load. Includes gamma, beta and impact factors. |
Total | Total M and V values due to all of the components listed above. |
Moments and shears for Service and Factored load combinations.
Reactions
Release Stresses
Setting | Description | ||||||
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Self wt | Stress due to girder self-weight only (considering release span).
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Prestress | Stress due to prestressing force only at transfer.
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Total | Total stress at release (due to prestress and self-weight).
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*(Asterisk) | Denotes stress exceeds allowable. |
Final Stresses: Positive Moment Envelope
Setting | Description |
---|---|
Prest/Precast-Top | Final stress at the top of the precast due to prestressing force. |
Prest/Bottom | Final stress at the bottom of the precast due to prestressing force. |
Self wt/Precast-Top | Final stress at the top of the precast due to self-weight of the beam. |
Self wt/Bottom | Final stress at the bottom of the precast due to self-weight of the beam. |
G-Prec/Precast-Top | Final stress at the top of the precast due to dead loads acting on the bare precast section. |
G-Prec/Bottom | Final stress at the bottom of the precast due to dead loads acting on the bare precast section. |
Topping/Precast-Top | Final stress at the top of the precast due to the weight of the topping on the bare precast section. |
Topping/Bottom | Final stress at the bottom of the precast due to the weight of the topping on the bare precast section. |
DL-Comp | Final stress due to superimposed dead load on composite obtained for a model of multi-span continuous beam with pier-to-pier spans. Composite is made from precast girder and topping. |
SG-Comp/Topping-Top | Final stress at the top of the topping due to superimposed dead loads on the composite section. |
SG-Comp/Precast-Top | Final stress at the top of the precast due to superimposed dead loads on the composite section. |
SG-Comp/Bottom | Final stress at the bottom of the precast due to superimposed dead loads on the composite section. |
QIm (+) | Final stress due to positive moments generated by live load. |
Total | Total final stresses due to all of the components listed above. |
Vertical Shear
Setting | Description |
---|---|
*(asterisk) | Denotes an IRC code violation. |
Vu | Total shear force due to ultimate loads. |
Vcl | Ultimate design shear force acting on precast section alone. |
Mpc | Ultimate design moment acting on the precast section alone. |
ec | Eccentricity distance of the cg composite section from centroid of strands. |
fcm | Stress at composite centroid due to Mpc. |
fcp | Stress at composite centroid due to prestressing. |
fcp-fin | 0.8fcp +fcm. |
fs | Stress at composite centroid due to shear, Vcl. |
Vco | Ultimate shear resistance of section uncracked in flexure, cl.14.1.2.2. |
Vcr | Ultimate shear resistance of section cracked in flexure, cl.14.1.3. |
Vcr_lim | Lower limit on Vcr. |
Av_min | Minimum shear reinforcement, clause 14.1.4. |
Av | Required area of shear steel. |
theta | Computed shear stress. |
Theta_max | Maximum shear stress based on concrete grade, table 6. |
Mt | Cracking moment at the section under consideration. |
d | Depth from extreme compression fibre to the centroid of the tendons at section. |
Along | Longitudinal shear reinforcement required, cl. 15.3. |
Avprvd | Provided area of shear reinforcement. |
Avprvd/Avrqrd | Ratio of provided vs. required shear reinforcement. |
Anchorage Zone Reinforcement
Setting | Description |
---|---|
Fpi | Force in strand, just before release. |
fs | Stress in steel. |
Abrst-req | Required steel area to be provided within a distance d/4 from the end of the beam. |
h/5 |
Distance (from end of beam) within which transverse reinforcement has to be provided h is the overall height of precast member. |
Horizontal Shear
Setting | Description |
---|---|
b |
Width of contact surface between the precast top flange and topping being investigated for horizontal shear. |
fsy | Yield strength of non-prestressed shear reinforcement. |
Vs |
Vertical shear due to dead load placed after composite section is effective and working live load with impact. |
VL | Longitudinal shear per unit length, cl. 611.4.1.3.3, IRC22-1986. |
Vlx | Computed ultimate bond stress at interface for rough bonding case. |
t-max | Ultimate bond stress limit. |
Camber and Deflections
Camber and deflections due to various loads, at the following stages:
Setting | Description |
---|---|
Release | Time at which the strands are cut in the prestressing bed. |
Erection | 30 to 60 days after release. |
Final | Long term. |
Mult | PCI camber and deflection multipliers. |
Prestress | Camber for prestress girder due to prestress only. |
Self Wt. | Deflection of girder under self-weight. |
Deck + Haunch | Girder deflection due to deck and haunch weight. |
G-Prec | Deflection of girder due to superimposed dead load on Precast. |
Diaphragm | Deflection of girder due to diaphragm loads. |
SG-Comp | Girder deflection due to superimposed dead load applied to composite model. |
Live Load | Deflection due to live load. |
Ultimate Capacity
Setting | Description |
---|---|
fck (girder-final) | Strength of the compression block concrete. |
As | Effective cross-sectional area of prestressing steel. |
c | Approximate depth of compression block for ultimate capacity computations. |
Mu-prvd |
Nominal moment of strength provided by the section. Must be greater than Mu. |
Mu | Required factored moment capacity. |
db | Depth of beam from max. compression edge to cg of steel. |
Mfyst | Capacity computed by yield of steel, under-reinforced section. |
Mfcrc | Capacity computed by crushing of concrete. |
Mult | Computer ultimate moment capacity. |
Mprvd/reqd | Ratio of ultimate moment capacity provided over required. |
Detensioning
Setting | Description |
---|---|
Groups | Number of group composed of one or two strands. |
Loss | Loss of prestress at release. |
Grp | Group number. |
Str | Number of strands in the group. |
Ys | Elevation of the center of gravity of the group of strands measured from the bottom of the beam. |
E | Elevation of the group of strands at the end of the beam. |
M | Elevation of the group of strands at the midspan of the beam. |
Ft | Stress at the top of the girder at a particular location. |
Fb | Stress at the bottom of the girder at a particular location. |
Final Stresses: Negative Moment Envelope
Reinforced Design
Setting | Description |
---|---|
fy | Specified yield strength of reinforcement. |
phi | Strength capacity reduction factor. For reinforcement over piers phi = 0.9 (Art. 8.16.1.2.2). |
f'c | Compressive strength of concrete at 28 days. End sections are designed using f'c. |
Sec | Sections for which reinforcement is calculated. |
Dist | Distance of the section measured from the left pier centerline. |
Mu-reqd | Total required factored moment. |
b | Width of compression block. |
hf | Thickness of flange under compression. |
bw | Web width of the beam. |
d | Effective depth. Distance from extreme compressive fiber to centroid of reinforcement in tension. Deck steel is assumed to be located at the midheight of the deck. |
d' | Distance from compression fiber center of gravity to centroid of compression steel (computed if necessary), which is assumed to be located 2.00 inches from the bottom flange of the beam. |
1.2*Mcr | 1.2 * cracking moment causing flexural cracking at section due to externally applied loads. |
Asb | Required amount of compression steel (bottom) for negative moments. Precast/Prestressed Girder computes the required amount of tension steel (Ast) in the deck (top), but occasionally bottom steel, assumed to be located at 2.0 inches from the bottom of the lower flange, is required to avoid an over-reinforced condition. |
Ast-r | Required amount of deck steel to resist total factored negative moment at a section. Amount required is only for the beam under consideration. It should be placed in the deck in accordance with Art. 8.17.2.1.1. |
Ast-p | Area of steel provided by the user in the Negative Moment Continuity Steel Tab on the Rebar dialog. |
M-prvd | Moment capacity computed based on user provided steel area. |
Reinforced Design (b) POSITIVE MOMENT AT PIERS
Setting | Description |
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Dist | Distance of the section measured from the left pier centerline. |
Ms | Positive Design Moment. Includes restraining moment and live load. |
b | Width of Compression block. |
hf | Thickness of Flange under Compression. |
bw | Web Width of Beam. |
d | Effective Depth. Distance from extreme compressive fiber to centroid of reinforcement in tension. Steel is assumed to be located at the 2 inches or 50 mm from the bottom flange of the beam. |
d' | Distance from compression fiber center of gravity to centroid of compression steel (computed if necessary), which is assumed to be 2 inches or 50 mm from the top of the deck. |
1.2Mcr | Cracking moment. |
Asb | Required amount of positive moment steel to resist larger of 1.2Mcr or Ms moment at a section. Amount required is only for the beam under consideration. |
Ast | Additional compression steel if required. |