Cantilever Sheet Pile Wall (English units)

Transcription

1 Cantilever Sheet Pile Wall (English units) Deep Excavation LLC Software program: DeepEX 2018 Document version: 1.0 August 14, DEEP EXCAVATION 1

2 A. Project description In this example we will design a cantilever sheet pile wall, supporting a 10 ft excavation. The Figure below presents the project model. Tables 1 and 2 present the soil properties and the stratigraphy respectively. Table 3 presents the external loads. Table 4 presents the wall properties. The general ground surface is at El. 0ft and the general water table is at El. -30 ft. Soil Layer Figure: Project model. Table 1: Soil properties. Design parameter Soil Type φ C /Su γ γdry ELOAD (deg) (psf) (pcf) (pcf) (ksf) F Fill C Clay S1 Sand S2 Sand Table 2: Stratigraphy. Soil Layer Elevation (ft) OCR Ko F C S S ERELOAD (ksf) DEEP EXCAVATION 2

3 Table 3: External loads. Load Load Type Start Point End Point Load Magnitude Load 1 Strip Surcharge (-51,0) (-1,0) 0.6 kips Table 4: Wall parameters. Left wall Sheet pile wall width 1.25 ft Steel pile material A 50 Sheet pile section AZ 14 Wall length 25 ft DEEP EXCAVATION 3

4 B. Modeling with DeepEX The model will be created using the DeepEX Model Wizard: Define Analysis Methods: Figure: Analysis Methods in DeepEX Wizard. In this dialog, we choose to apply Limit Equilibrium Analysis method to our model. For the classical earth pressures in design stages with multiple support levels we define FHWA apparent pressures and for the beam analysis we choose CALTRANS method. DEEP EXCAVATION 4

5 Define project type and dimensions Figure: Project Type and Dimensions in DeepEX Wizard. In this dialog we select the project type. In this case we select the option to create an anchored model, though it will not make any difference, since we will design a cantilever excavation. Next, we define the project dimensions (final excavation depth, walls depth, excavation width, top of the wall elevation and water table). DEEP EXCAVATION 5

6 Define soil types and stratigraphy Figure: Soil Properties and Soil Layers in DeepEX Wizard. Figure: Soil Properties and Soil Layers dialogs in DeepEX. In these dialogs we can define the required soil types and the properties for each created soil, as well as, the model stratigraphy by defining the top of the soil layer elevation and the soil type in each layer. DEEP EXCAVATION 6

7 Define wall type and wall section properties Figure: Wall types in DeepEX Wizard. Figure: Wall Sections dialog in DeepEX. In these dialogs we select the wall section type (in this case sheet pile wall), the sheet pile section, the wall spacing and the concrete steel materials. DEEP EXCAVATION 7

8 Define Stages Support Elevations Figure: Support Elevations in DeepEX Wizard. In this dialog, we select the option to create a cantilever excavation. DEEP EXCAVATION 8

9 Define Surcharge Figure: Support Elevations in DeepEX Wizard. In this dialog we define the surcharge type and properties, as well as the surcharge modeling options. In this case we will use a 0.6 kips strip surcharge, developed for 50 ft, starting 1ft behind the front wall. After the model is automatically generated by the software wizard, we can access the stages in the model area and add any required additional loads graphically, using the Draw Loads options in the General tab of DeepEX. DEEP EXCAVATION 9

10 Define structural codes: Figure: Structural Codes in DeepEX Wizard. In this dialog, we can define the structural and geotechnical design codes that we wish to assign to this model. In this case, we will use US allowable settings for steel design and ACI for concrete. DEEP EXCAVATION 10

11 The software automatically creates all project construction stages, according to our selections in the Model Wizard. The following Figures present the models in Stages 0 and 1 respectively: Figure: Generated Model Stage 0. Figure: Generated Model Stage 1. DEEP EXCAVATION 11

12 C. Results in DeepEX Since the model is ready, we can choose to calculate the design section, pressing on the button. After the analysis is succeeded, the Summary table appears. The table below includes some critical checks and values for each construction stage. The following figures present some graphical results from the results tab of DeepEX. Table: DeepEX critical results/stage Figure: Wall moment and shear diagrams, Stage 1. DEEP EXCAVATION 12

13 Figure: Wall deflections and soil pressures diagrams, Stage 1. Figure: Wall embedment safety factors, Stage 1. DEEP EXCAVATION 13