The web-application performs stress calculation for Steel Pipelines crossing Railroads and Highways as per API RP 1102. This design methodology relates to steel pipelines installed using trenchless construction methods, in particular auger boring, with the crossing perpendicular to the railroad or highway. The design performed by the web-application for the steel pipeline crossing is applicable in all scenarios where provisions of API RP 1102 code are applicable (refer clause 1.2 of API RP 1102) except the following:

- Two types of unit systems i.e. SI Unit & Customary Unit system can be selected for performing the calculation.

- The design methodology used in the program is such the pipelines having diameters of D = 2.375 to 48 inches (60.3 to 1219 mm) can be analysed. Values from various graphs of API RP 1102 for pipe diameter greater than 42 inch (1067 mm) is obtained by extra-plotting the graphs.

- The wall thickness to diameter ratios must be within the range of t
_{w}/ D = 0.010 to 0.080.

- Railroad crossings can be analysed for depths of cover H = 6 to 14 ft (1.8 to 4.3 m). Highway crossings can be analysed for depth of cover H = 3 to 10 ft (0.9 to 3.0 m).

- The loading condition for railroads if based for four axle distributed to the track surface, and would develop from the trailing and leading axle sets form sequential cars. Highway loadings are based on both single and tandem-axle truck loading configurations.

The methodology is broadly divided into four parts for designing railway or highway crossing of steel pipelines as per API RP 1102:

- Calculation of circumferential stress due to internal pressure by "Barlow formula" and check against allowable.
- Calculation of stresses due to external loads such as:
a) Stresses due to Earth Loadb) Stresses due to live load- Surface Live Load- Impact Factorc) Railroad Cyclic Stressesd) Highway Cyclic Stresses
- Calculation of principal stresses, effective stress and check against allowable
- Check for fatigue

B_{d}

Bored diameter of crossing

B_{e}

Burial factor for circumferential stress from earth load

D

Pipe outside diameter

E

Longitudinal joint factor

E'

Modulus of soil reaction

E_{e}

Excavation factor for circumferential stress from earth load

E_{r}

Resilient modulus of soil

E_{s}

Young’s modulus of steel

F

Design factor (barlow stress & fatigue check)

F_{a}

Allowable design factor (equivalent stress check)

F_{i}

Impact factor

G_{Hh}

Geometry factor for cyclic circumferential stress from highway vehicular load

G_{Hr}

Geometry factor for cyclic circumferential stress from rail load

G_{Lh}

Geometry factor for cyclic longitudinal stress from highway vehicular load

G_{Lr}

Geometry factor for cyclic longitudinal stress from rail load

H

Depth to the top of the pipe

K_{He}

Stiffness factor for circumferential stress from earth load

K_{Hh}

Stiffness factor for cyclic circumferential stress from highway vehicular load

K_{Hr}

Stiffness factor for cyclic circumferential stress from rail load

K_{Lh}

Stiffness factor for cyclic longitudinal stress from highway vehicular load

K_{Lr}

Stiffness factor for cyclic longitudinal stress from rail load

L

Highway axle configuration factor

L_{G}

Distance of girth weld from centerline

p

Maximum allowable operating pressure

N_{H}

Double track factor for cyclic circumferential stress

N_{L}

Double track factor for cyclic longitudinal stress

N_{t}

Number of tracks at railroad crossing

P_{s}

Single axle wheel load

P_{t}

Tandem axle wheel load

R

Highway pavement type factor

R_{F}

Longitudinal stress reduction factor for fatigue

S_{eff}

Total effective stress

S_{FG}

Fatigue resistance of girth weld

S_{FL}

Fatigue resistance of longitudinal weld

S_{He}

Circumferential stress from earth load

S_{Hi}

Circumferential stress from internal pressure

S_{Hi(Barlow)}

Circumferential stress from internal pressure calculated using the Barlow formula

S_{1}

Maximum circumferential stress

S_{2}

Maximum longitudinal stress

S_{3}

Maximum radial stress

SMYS

Specified minimum yield strength

T

Temperature derating factor

T_{1}

Installation temperature

T_{2}

Operating temperature

t_{w}

Pipe wall thickness

w

Applied design surface pressure

α_{T}

Coefficient of thermal expansion

γ_{T}

Unit weight of soil

S_{Hh}

Cyclic circumferential stress from highway vehicular load

S_{Hr}

Cyclic circumferential stress from rail load

S_{Lh}

Cyclic longitudinal stress from highway vehicular load

S_{Lr}

Cyclic longitudinal stress from rail load

ν_{s}

Poisson’s ratio of steel

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