Connection of Simple-Span Precast Concrete Girders for Continuity (2004) / Chapter Skim
Currently Skimming:
Appendix D - Design Examples
Appendix D - Design Examples
Pages 83-192
The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.
From page 83... ...
Reinforcement for Positive Moments at Interior Supports, D-50 D-54 DESIGN EXAMPLE 4: AASHTO BIII-48 BOX GIRDER (ADJACENT)
|
From page 84... ...
For the detailed design examples -- DE1 and DE4 -- a simple-span design is performed to compare with the twospans made continuous design. Both mild reinforcement and pretensioning strands are used to provide the positive moment connection between the precast girder and the continuity diaphragm.
|
From page 85... ...
The bridge typical section for DE3 is wider, while the bridge typical section for DE4 is narrower. The girder spacing and span length are fixed for each design example.
|
From page 86... ...
The positive design moments at the interior support are resisted by mild reinforcement or pretensioning strands that extend into the continuity diaphragm from the bottom flange of the girder. This positive moment connection is proportioned using strength design methods to resist any restraint moments that may develop or to provide a minimum quantity of reinforcement.
|
From page 87... ...
The girders are made continuous by a continuity diaphragm that connects the ends of the girders at the interior support. D-5 The connection is made when the deck slab is cast.
|
From page 88... ...
The factors are different for the indicated girder ages when continuity is established because the designs require different values for f ′c . • Girder self weight: The unit weight of girder concrete is 0.150 kcf.
|
From page 89... ...
Since the equations are sensitive to this quantity and the analysis for restraint moments is sensitive to creep and shrinkage values, it is important to carefully consider the computation of this ratio. The V/S ratio is generally computed using the equivalent ratio of the cross-sectional area to the perimeter.
|
From page 90... ...
LRFD Eq. C5.4.2.3.3-2 3.3.2 Deck and Continuity Diaphragm Concrete The same concrete properties are used for the deck slab and continuity diaphragm because they are placed at the same time in this example.
|
From page 91... ...
3.3.4 Mild Reinforcement Mild reinforcement is as follows: fy = 60 ksi, and Es = 29,000 ksi. 3.4 Stress Limits The following stress limits are used for the design of the girders for the service limit state.
|
From page 92... ...
Compressive stresses may be checked for the deck slab, but never govern, so they are not included here. Tensile stresses in the deck slab at interior supports should not be compared with limits for the service limit state because the deck is not D-10 prestressed.
|
From page 93... ...
The build-up is neglected when computing composite section properties that are used to calculate stresses for service limit state design since the build-up will vary along the bridge. However, for computation of section properties and strength calculations related to the reinforcement at the continuity diaphragm, the build-up is included.
|
From page 94... ...
that will be used to compute restraint moments; – Estimate the positive restraint moment, which is strongly dependent on girder age at continuity and time-dependent material properties; – Evaluate conditions at the continuity diaphragms to determine whether the connection is fully or partially effective under the effect of the positive restraint moment; – If the restraint moment exceeds 1.2Mcr or if the joint is not fully effective, it is recommended that the design or conditions be altered to improve the situation; – Analyze and design the girders for all design loads, including positive restraint moment (positive restraint moment should be neglected when evaluating stresses in regions of negative moment) ; – Design and detail a positive moment connection at continuity diaphragms; and – Design and detail reinforcement to resist negative moments from design loads, neglecting both positive and negative restraint moments.
|
From page 95... ...
(60 & 90) 83.1 –114.6 –131.2 N/A 54.0 N/A –815.8 Bearing 85.0 –129.3 –148.1 37.7 37.4 –924.8 –917.0 CL Pier 86.0 –137.0 –156.9 28.6 28.6 –975.7 –969.4 TABLE D-3.7.1-3 Service III design moments for loads on composite section
|
From page 96... ...
(60 & 90) 83.1 58.1 41.8 16.8 12.1 74.7 53.8 –143.2 –103.1 –196.9 –85.3 N/A 118.1 N/A –1,784.5 Bearing 85.0 0.0 0.0 0.0 0.0 0.0 0.0 –161.6 –116.4 –222.2 –96.3 82.4 81.7 –2,023.1 –2,005.8 CL Pier 86.0 N/A N/A N/A N/A N/A N/A –171.2 –123.3 –235.4 –102.0 62.4 62.3 –2,137.6 –2,120.2 TABLE D-3.7.2-1 Strength I design moments
|
From page 97... ...
Positive restraint moments are estimated, and their effect is considered in the design of the girders. The design for continuity at a girder age of 90 days is also discussed with the initial calculation of restraint moments.
|
From page 98... ...
However, two-span bridges have limited positive live-load moments at the interior support, while D-16 bridges with a greater number of spans can develop significant positive moments at interior supports from live load. The development of restraint moments with time is computed using the Restraint Program for the initial girder design.
|
From page 99... ...
The iterations continue until the revised positive restraint moment does not require a change in the strand pattern. Tables of strand requirements, positive restraint moments, and stresses at the bottom of the continuity diaphragm are given for the designs with girder ages at continuity of 28 and 60 days, respectively.
|
From page 100... ...
D-18 4.1.4.2 Girder Age at Continuity of 60 Days. The positive restraint moments shown in the table remain below the maximum positive restraint moment of 900.3 k-ft computed in Table D-4.1.1-1 for all iterations.
|
From page 101... ...
are compared with the limiting compressive stress for full dead load fc2 = 3.830 ksi. The maximum stress is 2.751 ksi at 0.50L for the combination with restraint moment (B)
|
From page 102... ...
The inclusion of positive restraint moments for the designs with earlier Iteration f 'ci f 'c Number of Strands Strand Diameter Positive Restraint Moment Stress at Bottom of Continuity Diaphragm Hold-down Location from End (ksi)
|
From page 103... ...
are compared with the limiting compressive stress for full dead load fc2 = 3.150 ksi. The maximum stress is 2.894 ksi at the interior transfer length location.
|
From page 104... ...
This design required more effort than the simplified approach, since positive restraint moments were included in the design. However, the design that established continuity when the girders were 28 days old required nearly 27% more strands than did the girder designed using the simplified approach.
|
From page 105... ...
are compared with the limiting compressive stress for full dead load fc2 = 3.150 ksi. The maximum stress is 2.638 ksi at the interior transfer length location.
|
From page 106... ...
5 REINFORCEMENT FOR POSITIVE MOMENTS AT INTERIOR SUPPORTS The connections between girders at interior supports of bridges made continuous are subject to positive design moments. However, the moments are caused by minor liveload effects (for more than two-span bridges)
|
From page 107... ...
5.2 Positive Design Moments For the strength limit state, the reinforcement in the positive moment connection is proportioned to provide a factored resisD-25 tance, φMn, greater than the larger of the factored moment, Mu, or 0.6Mcr, but not to exceed 1.2Mcr. A design moment of 1.2Mcr is typically provided because testing and field experience have shown that this quantity of reinforcement, which is also the minimum quantity of reinforcement required by the AASHTO LRFD Specifications in many cases, has performed well.
|
From page 108... ...
The minimum distance between the ends of girders should be determined early in the design process because design spans and continuity diaphragm dimensions depend on this distance. 5.4 Mild Reinforcement Mild reinforcement is often used to provide the positive moment connection.
|
From page 109... ...
3. Compressive stresses for full prestress and dead load are compared with the limiting compressive stress for full deadloadfc2 = 3.150 ksi.
|
From page 110... ...
The use of hairpin bars is especially helpful when a large number of bars is required to satisfy positive moment requirements. The development length for 90° hooked reinforcement should be used to compute the required embedment of 180° hooks into the continuity diaphragm.
|
From page 111... ...
5.4.3 Development and Detailing of Reinforcement into the Girder The required development length into the girder for the positive moment reinforcement is computed as follows: D-29 dh = 15.0 in.
|
From page 112... ...
The placement of the positive moment connection reinforcement between pretensioning strands increases congestion; this is significant because the congestion can inhibit the proper consolidation of concrete in the critical bearing area. Reinforcement should be positioned to facilitate placement and consolidation of concrete around the strands and bars.
|
From page 113... ...
The positive moments caused from restraint moments or temperature effects do not occur frequently enough to be considered as loadings that cause fatigue. However, for other bridge configurations, where the connection is subjected to tension from live loads, fatigue should be considered.
|
From page 114... ...
Extended strands used for the positive moment connection must be bonded at the end of the girder -- that is, they cannot be shielded or debonded at the end of the girder. 5.5.1 Development and Detailing of Extended Strands into Continuity Diaphragm The strands are developed into the continuity diaphragm using a 90° hook.
|
From page 115... ...
1.278 1.498 0.705 0.889 No. of Strands Req'd 5.9 6.9 4.6 5.8 60 & 90 Days Girder Age at Continuity WORKING STRESS DESIGN STRENGTH DESIGN 28 Days BASIC DESIGN INFORMATION TABLE D-5.5.2-1 Design information for positive moment connection using strand (critical values are shaded)
|
From page 116... ...
5.5.4 Crack Control The allowable tensile stress in the untensioned pretensioning strands in the connection would be computed using the same procedure as is used in Section 5.4.5. 5.5.5 Fatigue of Positive Moment Connection Reinforcement For information on fatigue of positive moment connection reinforcement, see Section 5.4.6.
|
From page 117... ...
6.1 Negative Design Moments Negative moments at interior supports of precast/prestressed concrete girders made continuous result from dead loads, live loads, and restraint moments. Negative restraint moments, however, are ignored in design, as allowed by the proposed Article C5.14.1.2.7b.
|
From page 118... ...
When the deck slab in a typical girder is subjected to tension from the effects of negative moments at the service limit state, tension reinforcement effective in resisting the tension must be placed within the width of deck equal to the lesser of (LRFD Article 5.7.3.4)
|
From page 119... ...
6.2.2.2 Anchorage of Deck Reinforcement. The LRFD Specifications indicate that the longitudinal reinforcement resisting the negative design moments must be anchored in concrete that is in compression at the strength limit state (LRFD Article 5.14.1.2.7b and proposed Article 5.14.1.2.7h)
|
From page 120... ...
6.2.5 Fatigue of Negative Moment Connection Reinforcement LRFD Article 5.5.3.1 states that "fatigue need not be investigated for concrete deck slabs in multigirder applications." However, the commentary for the article indicates that this provision is based on the observation of low measured stresses in deck slabs, which is "most probably due to internal arching action." The longitudinal reinforcement, which is acting as main reinforcement for the negative design moments at the interior support, is not subject to arching action. Therefore, fatigue of the deck slab reinforcement at the interior support is checked in this example.
|
From page 121... ...
The program first performs an analysis to estimate the development of restraint moments in the girders with time. This is similar to the analysis performed earlier in this example.
|
From page 122... ...
This is true for all situations for both positive and negative moments, except for the final positive restraint moment for continuity at 90 days. The final moments at 90 days for the two analysis methods are on both sides of the origin, making a relative comparison of values meaningless.
|
From page 123... ...
–95.3 –325.9 –503.5 % Change from Linear to Nonlinear –9.1% –7.3% –5.6% Note: Positive restraint moments are shown at a girder age of 7,500 days. Moments shown earlier were for a girder age of 10,000 days.
|
From page 124... ...
3.2.1 Girder Concrete Material properties required for this design example are f ′c = 7.00 ksi, and wc = 0.150 kcf. 3.2.2 Deck and Continuity Diaphragm Concrete The same concrete properties are used for the deck and continuity diaphragm because they will be cast at the same time.
|
From page 125... ...
D-43 3.3 Section Properties 3.3.1 Girder The section properties for a standard PCI BT-72 are h = 72.00 in., A = 767.0 in.2, I = 545,894 in.4, yb = 36.60 in., yt = 35.40 in., Figure D-2.1. Plan view of bridge.
|
From page 126... ...
The composite section properties used for girder design are similar, but are not used here because the deck has been transformed (deck and girder concrete compressive strengths are different) and the build-up was neglected.
|
From page 127... ...
Because the simplified approach is being used for this design example, restraint moment is not considered, so there is no positive design moment. In general, the reinforcement in the positive moment connection is proportioned using strength design to provide a factored resistance, φMn, greater than the larger of the factored moment, Mu or 0.6Mc, but not to exceed 1.2Mcr.
|
From page 128... ...
Detail of reinforcement placement at positive moment connection (section view)
|
From page 129... ...
One example is that the positive moment reinforcement must avoid locations of headed studs attached to embedded plates. 4.3.4 Development of Reinforcement into Girder The positive moment reinforcement must be developed into the girder (see discussion in DE1)
|
From page 130... ...
3.2.1 Girder Concrete Material properties required for this design example are as follows: f ′c = 6.00 ksi, and wc = 0.150 kcf. 3.2.2 Deck and Continuity Diaphragm Concrete The same concrete properties are used for the deck and continuity diaphragm because they will be cast at the same time.
|
From page 131... ...
: h = 51.0 in., A = 908.0 in.2, I = 309,865 in.4, yb = 22.95 in., yt = 28.05 in., Sb = 13,502 in.3, and St = 11,047 in.3. 3.3.2 Continuity Diaphragm The section properties of the continuity diaphragm are required to compute the cracking moment.
|
From page 132... ...
4 REINFORCEMENT FOR POSITIVE MOMENTS AT INTERIOR SUPPORTS The connections between girders at interior supports of bridges made continuous are subject to positive design Half Section in Span Half Section at Continuity Diaphragm Figure D-2-3. Typical section of bridge.
|
From page 133... ...
This recommendation is based on providing the connection to enhance the structural integrity of the structure so that it may be more robust and better able to resist unforeseen or extreme loads. Since the simplified approach is being used, where restraint moments are not computed, a positive moment connection is not required.
|
From page 134... ...
The much larger section of the continuity diaphragm results in a larger design moment than for the other sections considered in these design examples. However, the area in which the reinforcement can be placed is also much greater.
|
From page 135... ...
6 bars is 18 in. 4.3.5 Termination of Positive Moment Reinforcement The termination of positive moment reinforcement in the girder should be staggered.
|
From page 136... ...
In a two-span bridge made continuous, positive moments at the interior pier develop only from restraint moments. These positive design moments are resisted by mild reinforcement or strands that are extended into the continuity diaphragm from the bottom flange of the girder.
|
From page 137... ...
This was supplemented by hand and spreadsheet computations to obtain the quantities needed for this design. Restraint moments were estimated using the RESTRAINT Program that was developed as part of this research project.
|
From page 138... ...
on the design truck. Live-load distribution factors are computed using equations in LRFD Table 4.6.2.2.2b-1 for Figure D-2-2.
|
From page 139... ...
See the AASHTO LRFD Specifications for secondary equations and complete definitions of the terms used in the calculations that follow. Restraint moments are very sensitive to variations in creep and shrinkage values, so possible estimates should be used.
|
From page 140... ...
3.3.3.1 Transfer Length. The stress in the pretensioning strands is transferred from the strands to the girder concrete over the transfer length.
|
From page 141... ...
3.4 Stress Limits The following stress limits are used for the design of the girders for the service limit state. For computation of girder stresses, the sign convention will be compressive stress is positive (+)
|
From page 142... ...
Restraint moments are not shown in tables contained in this section. Computations are made later in the example.
|
From page 143... ...
It is highly recommended that the minimum age for continuity be specified in the contract documents. Analytical studies and field experience indicate that waiting to establish continuity until the girders are at least 90 days old will significantly reduce or eliminate the development of positive restraint moments.
|
From page 144... ...
; – Design and detail a positive moment connection at continuity diaphragms; and – Design and detail reinforcement to resist negative moments from design loads, neglecting both positive and negative restraint moments. • Simplified Approach: – Specify the minimum age of the girders when continuity is established in the contract documents; the minimum girder age at continuity must be at least 90 days; – The connection at continuity diaphragms may be taken to be fully continuous; – Analyze and design the girders for all design loads (neglect restraint moments)
|
From page 145... ...
Positive restraint moments are estimated, and their effect is considered in the design of the girders. The design for continuity at a girder age of 90 days is also discussed with the initial calculation of restraint moments.
|
From page 146... ...
Positive restraint moments are generally larger for two span bridges than for bridges with a greater number of spans with similar span lengths, given the same span lengths and other conditions. However, two-span bridges have limited positive live-load moments at the interior support, while bridges with a greater number of spans can develop significant positive moments at interior supports from live load.
|
From page 147... ...
While other quantities, such as strand size or concrete strengths, had to be adjusted in DE1 during the iterations, only the strand pattern was revised for this problem. Tables of strand requirements, positive restraint moments, and stresses at the bottom of the continuity diaphragm are given below for the designs with girder ages at continuity of 7 and 28 days.
|
From page 148... ...
are compared with the limiting compressive stress for full dead load fc2 = 2.700 ksi. The maximum stress is 1.763 ksi at the transfer length location for the combination without restraint moment (A)
|
From page 149... ...
However, a design iteration was run for the girder with this additional positive moment, and it was found that the initial strand pattern was adequate to resist the additional moment without any revisions. This result appears to support the provisions in the proposed specifications allowing positive restraint moments to be neglected for a design with continuity established at a girder age of at least 90 days, even when a composite deck slab is not used.
|
From page 150... ...
are compared with the limiting compressive stress for full dead load fc2 = 2.700 ksi. The maximum stress is 1.421 ksi at the transfer length location for the combination without restraint moment (A)
|
From page 151... ...
The design for a girder age of 90 days at continuity was performed using the simplified approach, in which positive restraint moments are neglected. The inclusion of positive restraint moments for the designs with earlier continuity resulted in larger positive design moments within the spans, which required an increase in the number of prestressing strands.
|
From page 152... ...
are compared with the limiting compressive stress for full dead load fc2 = 2.700 ksi. The maximum stress is 1.252 ksi at the transfer location for the combination without restraint moment (A)
|
From page 153... ...
Top number in cells is positive restraint moment at interior support. Bottom number in cells is Service III maximum positive design moment at midspan.
|
From page 154... ...
This recommendation is based on providing the connection to enhance the structural integrity of the structure so that it may be more robust and better able to resist unforeseen or extreme loads. However, if analysis for restraint moments is required and the analysis indicates that a positive moment will develop, the proposed specifications require that a positive moment connection be provided.
|
From page 155... ...
5.4 Mild Reinforcement Mild reinforcement is often used to provide the positive moment connection. The reinforcement for the connection must extend from the end of the girder and be anchored into the continuity diaphragm.
|
From page 156... ...
Extra attention must be given to this area during placement of concrete to avoid a lack of consolidation. However, the fact that the girder in this design example is a box section greatly improves the ability to provide positive moment reinforcement without a significant increase in congestion.
|
From page 157... ...
5.4.3 Control of Cracking by Distribution of Reinforcement According to LRFD Article 5.7.3.4, the reinforcement will be proportioned so that the tensile stress in the mild steel reinforcement at the service limit state does not exceed the stress limit given by LRFD Equation 5.7.3.4-1. Since there are no positive service limit state moments, this calculation is not necessary.
|
From page 158... ...
These factors tend to lead designers to use a larger number of smaller bars. The placement of the positive moment connection reinforcement between pretensioning strands increases congestion.
|
From page 159... ...
5.5 Pretensioning Strand An alternate positive moment connection uses pretensioning strands extended into the continuity diaphragm. Because a positive moment connection with strands uses existing reinforcement (strands)
|
From page 160... ...
Based on these stress limits for service and strength limit states, the number of strands required to resist the positive design moments is computed. The design moments are governed by the minimum limits of Mcr = 486.7 k-ft and 1.2Mcr = 584.1 k-ft for service and strength design, respectively.
|
From page 161... ...
6.1 Negative Design Moments Negative moments at interior supports of precast/prestressed concrete girders made continuous result from dead loads, live loads, and restraint moments. Negative restraint moments, however, are ignored in design, as allowed by proposed Article 5.14.1.2.7b.
|
From page 162... ...
6.2.2 Details of Negative Moment Reinforcement The negative moment connection reinforcement can be detailed using the same details that are used for the positive moment connection with mild reinforcement except that the hooks are turned down into the continuity diaphragm as shown in Figure D-6.2.1-1. An alternate negative moment connection may be made by splicing straight bars across the continuity diaphragm.
|
From page 163... ...
6.2.2.1 Anchorage of Negative Moment Reinforcement. The specifications indicate that the longitudinal reinforcement resisting the negative design moments must be anchored in concrete that is in compression at the strength limit state (LRFD Article 5.14.1.2.7b and proposed Art.
|
From page 164... ...
and the load factor for the fatigue limit state, which is 0.75 (LRFD Table 3.4.1-1)
|
From page 165... ...
; and r/h = ratio of base radius to height of rolled on transverse deformations in the reinforcement = 0.3 may be used if value not known. Comparing the computed stress range to the limiting stress range, ff = 6.63 ksi < ff max = 17.3 ksi.
|
From page 166... ...
Ma, Z., Huo, X., Tadros, M.K., and Baishya, M "Restraint Moments in Precast/Prestressed Concrete Continuous Bridges," PCI Journal, Vol.
|
From page 167... ...
Input Girder Concrete Utlimate Creep Coefficient Cross Sectional Area of Strand (in 2 ) Deck Concrete Compressive Stress at 28 Days (psi)
|
From page 168... ...
Deck Concrete Compressive Stress at 28 Days Centroid of Draped Strands at Girder End Centroid of Draped Strands at Midspan Span Data Select Girder Type Exterior Span Length (ft) Number of spans Include Dischinger Effect?
|
From page 169... ...
Input Girder Concrete Utlimate Creep Coefficient Cross Sectional Area of Strand (in2) Deck Concrete Compressive Stress at 28 Days (psi)
|
From page 170... ...
Time Data Input Girder Concrete Utlimate Creep Coefficient Cross Sectional Area of Strand (in 2 ) Deck Concrete Compressive Stress at 28 Days (psi)
|
From page 171... ...
Time Data Input Girder Concrete Utlimate Creep Cross Sectional Area of Strand (in2) Deck Concrete Compressive Stress at 28 Days Centroid of Draped Strands at Girder End Centroid of Draped Strands at Midspan Span Data Select Girder Type Exterior Span Length (ft)
|
From page 172... ...
If Yes, Deck Age for Dischinger Modification Relative Humidity Deck Concrete Ultimate Shrinkage Girder Concrete Ultimate Shrinkage Deck Concrete Unit Weight Input Girder Concrete Utlimate Creep Cross Sectional Area of Strand (in2) Deck Concrete Compressive Stress at 28 Days Centroid of Draped Strands at Midspan Span Data Select Girder Type Exterior Span Length (ft)
|
From page 173... ...
Time Data Input Girder Concrete Utlimate Creep Cross Sectional Area of Strand (in2) Deck Concrete Compressive Stress at 28 Days Centroid of Draped Strands at Girder End Centroid of Draped Strands at Midspan Span Data Select Girder Type Exterior Span Length (ft)
|
From page 174... ...
If Yes, Deck Age for Dischinger Modification Relative Humidity Deck Concrete Ultimate Shrinkage Girder Concrete Ultimate Shrinkage Deck Concrete Unit Weight Input Girder Concrete Utlimate Creep Cross Sectional Area of Strand (in2) Deck Concrete Compressive Stress at 28 Days Centroid of Draped Strands at Midspan Span Data Select Girder Type Exterior Span Length (ft)
|
From page 175... ...
If Yes, Deck Age for Dischinger Modification Relative Humidity Deck Concrete Ultimate Shrinkage Girder Concrete Ultimate Shrinkage Deck Concrete Unit Weight Input Girder Concrete Utlimate Creep Cross Sectional Area of Strand (in2) Deck Concrete Compressive Stress at 28 Days Centroid of Draped Strands at Midspan Span Data Select Girder Type Exterior Span Length (ft)
|
From page 176... ...
If Yes, Deck Age for Dischinger Modification Relative Humidity Deck Concrete Ultimate Shrinkage Girder Concrete Ultimate Shrinkage Deck Concrete Unit Weight Input Girder Concrete Utlimate Creep Cross Sectional Area of Strand (in2) Deck Concrete Compressive Stress at 28 Days Centroid of Draped Strands at Midspan Span Data Select Girder Type Exterior Span Length (ft)
|
From page 177... ...
D-95 SUBAPPENDIX B: INPUT AND OUTPUT FROM RESPONSE 2000 DB.1 PROGRAM INFORMATION The Response 2000 Program was developed at the University of Toronto and is available free of charge at www.ecf. utoronto.ca/~bentz/r2k.htm.
|
From page 178... ...
D-96 Girder Midspan - 90 Days TJT 8/20/2002 All dimensions in inches Clear cover to reinforcement = 1.75 in Inertia (in4)
|
From page 179... ...
D-97 End of Girder - 90 Day TJT 8/20/2002 All dimensions in inches Clear cover to reinforcement = 1.75 in Inertia (in4)
|
From page 180... ...
D-98 Diaphragm - 90 Day TJT 8/20/2002 All dimensions in inches Clear cover to reinforcement = 1.69 in Inertia (in4)
|
From page 181... ...
D-99 Girder Midspan - 60 Day TJT 8/20/2002 All dimensions in inches Clear cover to reinforcement = 1.75 in Inertia (in4)
|
From page 182... ...
D-100 End of Girder - 60 Day TJT 8/20/2002 All dimensions in inches Clear cover to reinforcement = 1.75 in Inertia (in4)
|
From page 183... ...
D-101 Diaphragm - 60 Day TJT 8/20/2002 All dimensions in inches Clear cover to reinforcement = 1.69 in Inertia (in4)
|
From page 184... ...
D-102 Girder Midspan - 28 Days TJT 8/20/2002 All dimensions in inches Clear cover to reinforcement = 1.70 in Inertia (in4)
|
From page 185... ...
D-103 End of Girder - 28 Days TJT 8/20/2002 All dimensions in inches Clear cover to reinforcement = 1.70 in Inertia (in4)
|
From page 186... ...
D-104 Diaphragm - 28 Days TJT 8/20/2002 All dimensions in inches Clear cover to reinforcement = 2.44 in Inertia (in4)
|
From page 187... ...
• Design Example 4: AASHTO BIII-48 Adjacent Box Girder Bridge -- The design spans for the bridge in this example are the same as Design Example 1; therefore, the output from Design Example 1 (see Section DC.1) was used for this example.
|
Key Terms
This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
More
information on Chapter Skim is available.