751.32 Concrete Pile Cap Intermediate Bents
751.32.1 General
751.32.1.1 Material Properties
Concrete | |||
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Typically, shall consist of: | |||
Class B Concrete (Substructure) | Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle \, f'_c} | = 3.0 ksi | |
Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle \, n} | = 10 |
In addition, Class B-1 Concrete (Substructure) may also be used in special cases (See Project Manager). The following equations shall apply to both concrete classes:
Concrete modulus of elasticity:
Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle \, E_c = 33000 K_l w_c \sqrt [1.5]{f'_c}}
Where:
= unit weight of non-reinforced concrete = 0.145 kcf | |
Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle \, K_l} | = correction factor for source of aggregate = 1.0 |
Modulus of Rupture: | For minimum reinforcement, | Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle \, f_r = 0.37 \sqrt {f'_c}} |
For all other calculations, | Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle \, f_r = 0.24 \sqrt {f'_c}} | |
Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle \, \sqrt{f'_c}} is in units of ksi |
Reinforcing Steel
Minimum yield strength, | Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle \, f_y} | = 60.0 ksi |
Steel modulus of elasticity, | = 29000 ksi |
751.32.2 Design
751.32.2.1 Limit States and Factors
In general, each component shall satisfy the following equation:
Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle \, Q = \sum \eta_i \gamma_i Q_i \le \phi R_n = R_r}
Where:
Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle \, Q} | = Total factored force effect |
Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle \, Q_i} | = Force effect |
Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle \, \eta} | = Load modifier |
Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle \, \gamma_i} | = Load factor |
= Resistance factor | |
Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle \, R_n} | = Nominal resistance |
Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle \, R_r} | = Factored resistance |
Limit States
The following limit states shall be considered for bent design:
- STRENGTH – I
- STRENGTH – III
- STRENGTH – IV
- STRENGTH – V
- SERVICE – I
- FATIGUE
See LRFD Table 3.4.1-1 and LRFD 3.4.2 for Loads and Load Factors applied at each given limit state.
Resistance factors
- STRENGTH limit states, see LRFD 5.5.4.2
- For all other limit states, Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle \, \phi} = 1.00
751.32.3 Details
751.32.3.1 General
(*) 3" (Typ.) | |
Part Elevation | Part Section |
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751.32.3.2 Front Sheet
Note: | The following are details and dimensions for the Plan View on the Front Sheets. |
Details for unsymmetrical roadways will require dimensions tying Centerline Lane to Centerline Structure. |
751.32.4 Reinforcement
751.32.4.1 General
Part Elevation | Section Thru Beam |
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Part Plan |
* #4 Bars () not required for Double-Tee structures | |
Reinforcement Under Bearings | |
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Transverse Beam Steps - Over 3" or Steps Accumulating Over 3" |
Part Plan | |
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Over 3" thru 12" | Over 12" |
Longitudinal Beam Steps |