Comparative Study & Design Optimization Of Rob Pier Pile Foundation With Bow String Girder Superstructure

Comparative Study & Design Optimization Of Rob Pier Pile Foundation With Bow String Girder Superstructure

Sandeep Kumar

M. Tech Students, Department of Civil Engineering, World College of Technology and Management,

Ankit Sethi

Assistant Professor, Department of Civil Engineering, World College of Technology, Gurugram-122506, India, and Management, Gurugram-122506, India

Abstract – This study examines the cost-effectiveness and design optimization of Pile Foundation of Pier of Road Over Bridge (ROB) with Bow String Girder superstructure. Optimum and safe design of Bridge especially in case of Bow String Girder Superstructure is very challenging task.

For this study ROB pier with wall type substructure and Bow String Girder superstructure of 64m span RDSO standard drawing RDSO/B-10427 and 4 lane carriageway adopted. Pile foundation of 10 Piles group with 1.2m dia of pile adopted.

For this IRC loading applied such as live load (4 lanes of Class A, 2 Lane of Class A+1 Lane of 70R, 1 Lane of 70R, 3 Lane of Class A, Special Vehicle Loading), Seismic Loading, wind load, dead load, wearing coat, crash barrier etc. FEM analysis done to get the benefit of design software to achieve the best results. Structure lies in the seismic Zone IV, so it is very important to study the effects of seismic loading over the structure and ultimately over the foundation.

Analysis covered the pier width varies from 6m to 12m. Results showed that with increase in the pier width pile reinforcement increases from 1.99% to 2.36%. In another study pier width kept constant and thickness keep changing from 0.90m to 1.5m. In this case pile reinforcement changes from 2.13% to 2.36%. These variations occur mainly due to changes in seismic forces.

Keywords- Pile, Pier, Seismic force, Bending Moment, Finite Element Analysis.

1. INTRODUCTION

   Bow String girder is an arch bridge. Whenever the highway alignment passes over the railway lines a bridge needs to be proposed over the railway tracks for free flow of traffic and that bridge is called Road over Bridge (ROB). If the span of proposed bridge is less than 50m composite plate girder can be proposed, but if the span is of 50m or exceeds the 50m length then Bow String girder is proposed.

   The substructure height over which the Bowstring girder rested, depends on the vertical clearance between the girder soffit and rail top levels. Railway department specifies the vertical clearance minimum 6.5m, in some cases it may be vary unto 7.5m. For ROBs wall type pier are preferred because the wall type piers offer more resistance to accidental load that is necessary to check for ROB pier as per railway standards. However, in some cases Portal frame type pier with circular column 2 or 3 numbers are also provided.

   Pile foundations are mostly preferred and recommended for such heavy load. Because pile foundations offer more safe load bearing capacity than open foundation. Pile foundations are safer for such heavy dead load, live load and seismic loads. Pile foundations transfer the load safely to deeper hard strata.

2. LITERATURE REVIEW

   Patel Nirav M, Prof. Deepa H. Raval [1] studied the design and economic aspects of tall pier and foundation of bridge. They mainly studied the effects of parametric changes such as pier height, concrete grade, reinforcement grade, substructure type, reinforcement dia etc. and finally studied the cost effects of all the parametric changes. The study

   based on IRC and IS code specifications. Is also studied the seismic effects on pier and foundation. Study used STAAD Pro software for FEM analysis. Analysis conducted on 6 different heights of pier ranges from 30m to 100m (30m, 50m, 70m, 80m, 90m and 100m).

   Though this studied the bridge pier and its foundation for different heights, the superstructure span (25m) is not so large. So, the study lacks the heavy superstructure load and pile foundation parameter are not defined clearly and the study mainly focused on the substructure.

   Makoto Kimura, Shinya Inazumi, Yoshikazu Nishiyama, Hirikuni, Masanori Kobayashi, Masami Ochiai [2] This study presents the development and potential of newly developed H-joint steel pipe sheet piles of bridge pier foundation. This study shows how the steel pipe sheet piles (SPSP) are developed, tested before use and the site execution. The findings of the study are listed as: i) these type piles are installed with high driving pressure. ii) The joints of the sheet piles are strong in bending. iii) due to high rigidity lateral bearing capacity is high. iv) helps in reducing the number of piles and labour cost.

   The study doesnt depict the superstructure & substructure load for which the sheets piles are designed for bridge piers. It also not specifies the H section properties used for the joint, which is the main element of these types of piles. Though it presents the different method and material for bridge pier foundation piles, but are not so viable than the conventional RCC bored cast-in-situ piles.

   Seungho Kim, Sangyong, Seoung-Wook Whang, Won Gil Hyung [3] This study explains the application of extended end composite pile. This work mainly focused on foundation of high-rise buildings. For the sake of safety of and high bearing capacity, pretensioned high strength concrete piles (PHC) have been put to practical use. However, PHC piles have limited bearing capacity, leading to the congested layout and thus finally results in high construction cost. To overcome this steel PHC composite piles have been developed. These types of piles have low cost and high bearing capacity. Other type of piles known as extended end pile have high bearing capacity.

   Though these types of piles have high bearing capacity, however the research work done on building site and there is no study for seismic forces and bridge foundation.

   Prakriti Sharma B. Eng. Pokhara University, 2015 [4] This study based on the comparative study of different methods for superstructure-foundation interactions. Soil -pile interaction by STAAD software analysis completed. A case study of 3×24.4m with pile foundation adopted. Propertied of soil at different layers assigned as spring constant. Superstructure response represented by bending moment and deflection. Different design / analysis approaches are discussed in this study such as Integrated analysis process (IAP) Simplified Boundary Condition (SBC) approach, Maximum allowable displacement (MAD) approach, equivalent pile length (EPL) approach.

   In IAP method substructure and superstructure elements were analysed holistic approach whereas in other methods superstructure and foundation are analysed separately.

   Gianpiero Russo [5] Analysis and design of pile foundations under vertical load is studied under this research. Load sharing and interaction between the piles and connecting raft is a key factor in optimum design. In this study the effects of installation technique discussed on the basis of experimental data received from different sites. Bearing capacity-based design and settlement-based design are compared to find which one method is more suitable for optimum design.

   The installation technique on pile performance under vertical load. The performance mainly depends on the dia of pile, surrounding soil characteristics and vertical load coming over it. Though this study discusses the pile behaviour subjected to vertical load in building structure, it doesnt discuss about pile foundation of bridge structure.

3. BRIDGE INPUT DATA

   The bridge input data use for analysis listed as below:

   Main ROB Span: Pier:

   Pile:

   64.000m (RDSO/B-10427)

   12.0×1.2m (Wall Type)

   1.2m Dia, 10 Piles

   Fig.1-Details of ROB Span Bow String Girder

   Fig.2 Details of Pier Cross Section

   Fig.3 Details of Pile Group and Pier Elevation

4. METHODOLOGY

   For the analysis FEM model is prepared in the STAAD pro as per the pier specifications. Pile and pier are modelled in the software. Spring constant applied as per the Geotech exploration SPT N values and IS:2911 (Part1/Sec2):2010. Once the model is complete apply 1000kN load in longitudinal and transverse direction for stiffness calculation. On the basis of stiffness time period and seismic coefficient and seismic forces calculated. To optimize the pile foundation seismic forces should calculated carefully, because in this analysis, seismic load combination is governing one.

   Following load data used for the analysis:

   Dead load Superstructure: As per RDSO/B-10427 Crash Barries: 1.5t/m

   Wearing Coat: 0.2t/m2

   Seismic Zone (Z): IV

   Importance Factor (I): 1.2

   Live Load: As per IRC:6-2017

   The results obtained from the analysis tabulated in the table 1 & 2

   Fig. 4 3D FEM Model of Pier with Pile Foundation

   TABLE 1!: MAXIMUM & MINIMUM REACTION OVER PILE

   	1!	2	3	4	5	,6	7	8	9	10	11	12	horizonta I force
   	Tollll.e	Tollll.e	Tollll.e	Tonne	Tollll.e	Tollll.e	Tollll.e	Tollll.e	Tonne	Tollll.e	Tollll.e	Tonne	Tollll.e
   LC-11	205	205	205	205	205	466	466	466	466	466			8.0
   LC-2	3119	3119	3119	3119	3119	460	460	460	460	460			6.11
   LC-3	282	293	303	3113	324	546	556	566	5				112.11
   LC-4	2’9	289′	300	31111	3211	5511	5611						1111.2
   LC-5		1139	b9	1139	1139	34				34			6.9
   LC-6		22′	22′	22′	22′	344			344	344			5.J

   Pile Reaction ovei: Pile No.

   LC-LC-8

   1195

   1192

   204

   2011

   2113

   21111

   222

   220

   2311

   229

   118

   423

   454

   460

   LC-9 LC-110

   1134

   ‘9’

   1511

   156

   1169

   1186

   2’3

   204

   332

   445

   311 3

   LC-1111 11 6

   1163

   1198

   2116

   4611 4

   LC-112

   1109

   1168

   285

   344

   333 3

   450

   LC-113 LC-114 LC-115 LC-116

   ’90

   -22

   1122

   9

   1134

   1123

   1165

   155

   209

   3011

   222

   4115

   253

   365

   5611

   29′

   5’92

   4811

   1185

   5114

   2118

   525

   3311

   558

   364

   569

   4

   602

   5110

   6113

   623

   646

   656

   656

   69

   689

   802

   33.8

   811.11

   33.8

   811.11

   LC-11 LC-118 LC-119 LC-20

   LC-211

   1133

   114

   1164

   5

   11311

   11 8

   225

   311

   25

   349

   224

   468

   .J04 500

   zo

   3118

   620

   350

   652

   311

   440

   1138

   4 3

   11 11

   4411

   486

   290

   520

   323

   488

   533

   4411

   566

   4 5

   534

   625

   44

   65:9

   8

   5811 62′

   311.2

   82.11

   311.2

   82.11

   3112

   LC-22

   112

   1164

   3116 46

   6119

   b9′ 2911

   443

   5:9’5 46

   822

   LC-23

   1162

   209′ 256

   302

   349

   4 5 522

   568

   6115

   662

   3112

   LC-24

   195 34

   499

   6511

   11 3

   325 4

   629′ 80

   822

   LC-25 LC-36

   CAPACITY DESIGN

   353

   338

   355

   3.J9

   356

   3411

   358

   3 2

   495

   504

   496

   505

   500

   508

   5011

   509

   6.11

   6.11

   LC-29	-85	67	-50	-32	-15	664	681	699	717	734		48.5
   LC-.:,0	– 1	-54	-36	-18	-1	6 8	695	13	31	48		485
   LC-31	-89	-45	-l	43	86	660	04	48	91	835		53.2
   LC-32	-57	-13	31	75	119	692	736	780	824	867		532
   LC-33	-88	-42	5	51	9	661	0	53	800	846		53.4
   LC-34	-56	_:9	3	84	130	693	40	86	833	8 9		53.4
   LC-35	-88	-42	5	51	98	661	707	754	800	847		53.4
   LC-36	-56	-9	38	84	131	693	40	86	833	880		53.4

   ‘

   TABLE 2 ULS Design Check for Pile									( SHEAR CAPACITY [LONGITUDINAL DIRj
   LC	Pile Reaction			Mon1.e.11t NIED		Mon1.e.11tMRD		Check (l\..{ED< MRD)
   	‘i erticLoad		Hoo ntaJ	M= Q(L1l + Lf)/		Fico!IJl1 lncraction			G”ep = NED/Ac	‘iR,!le	C.keck
   	Max	M:i!i1				M.,. ]r.fin NED l NED					HL < VR<oe
   	Tonne	Tonne	Tonne	Tm		Tm			N/i:nnl	Tonne
   LC-1	466	205	8	43 38 64 60 37 33 – – ‘.)’.) 52 89 1l88 89 188 l 9 43] H9 43] 1l65 436 165 436 165 436 165 436 33 33		506	496	OK	4	0	OK
   LC-2	460	31l9	7			506	5L	OK	4	69	OK
   LC-3	58	282	]2			501	513	OK	5	82	OK
   LC-4	594	279	H			501	513	OK	5	83	OK
   LC-5	347	1l39	7			51l1	480	OK	3	58	OK
   LC-,6	344	227	6			51l1	50]	OK	3	58	OK
   LC-7	454	1l95	]0			506	494	OK	4	6:9	OK
   LC-8	460	192	]O			506	493	OK	4	69	OK
   LC9	51l6	1l34	n			504	478	OK	5	75	OK
   LC-1l0 LC-l1l	552 532	9r7 146	35 n			503 503	469 48]	OK OK	5 5	79	OK OK
   LC-l2	568	109	35			502	4 2	OK	5	BO	OK
   LC-13 LC-1l4	656 69	90 -?’)	34 B1l		I	::e9:B..-R.._468 1:749t_.		OK OK		89 ]01l	OK OK
   					F I
   LC-1l5	689	1l22	34			4		O&		93	OK
   LC-1l6	802	9	B1l			493 44		OK	7	]04	OK
   LC-1l7	625	1lJJ	31l			500 478		OK	6	86	OK
   LC-18	744	1l4	82			495 449		OK	7	98	OK
   LC-19	659	164	31			498 486		OK	6	89	OK
   LC-20	B	45	82			494 45		OK		]01l	OK
   LC-21l	62	U-1	31			500 4 B		OK	6	86	OK
   LC-22	46	1l2	82			495 449		OK		98	OK
   LC-23	662	162	31			498 485		OK	6	90	OK
   LC-24	BO	43	82			494 456		OK		102	OK
   LC-25	501	352	6			505 510		OK	4	4	OK
   LC-26	509	337	6			504 51]		OK	5	74	OK
   CAPACITY DESIGN
   LC-29	34	-85	49	258		495	425	OK	6	9	OK
   LC-JO	48	– 1l	49	258		495	428	OK		98	OK
   LC-3]	835	-89	53	282		49]	424	OK	7	1l07	OK
   LC-32	867	-57	53	282		490	432	OK	8	no	OK
   LC-33	846	-88	5J	284		49]	424	OK		108	OK
   LC-34	8 9	-56	5J	284		490	432	OK	8	n2	OK
   LC-35	847	-88	53	284		49]	424	OK	7	1l08	OK
   LC-36	880	-56	53	284		490	432	OK	8	n2	OK

   -·-

5. RESULTS & DISCUSSIONS

   For the pile optimization motive, different iterations are done with the pier parameters changes. In first trial pier width vary from 12.0m to 6.0m and in another trial thickness changes from 1.5m to 0.9m. If only the pile reinforcement and pile cost considered then 1.2×6.0m is the most economical combination. However, in case of Bow String Girder for 17.0m width carriageway with 18.125m baring to bearing transverse pier cap is almost 21.0m. For such large pier cap 6.0m pier width is too short because in this case pier cap cantilever will be 7.50m. For bow string girder of 64m span such large pier cap cantilever is not feasible. So, 1.2×10.0m pier shaft is best pier dimension.

   Change in Pile Reinforcement with Change in Pier Dimension

   27000

   26000

   25000

   24000

   23000

   22000

   21000

   20000

   6

   7

   8

   9

   Pier Size (m)

   10

   11

   12

   Change in %age of Pile Reinforcement with Change in Pier Dimension

   2.4

   2.3

   2.2

   2.1

   2

   1.9

   1.8

   6

   7

   8

   9

   Pier Size (m)

   10

   11

   12

   %age of Reinforcement (mm2)

   Area of Reinforcement (mm2)

   Fig. 5 Change in Pile Reinforcement area w.r.t. Pier Dimension

   Fig. 6 Change in Pile Reinforcement %age w.r.t. Pier Dimension

6. CONCLUSION

   After the parametric study of Bridge pier to analyse the effect on pile foundation, it is found that with the increase in the pier width or thickness pile reinforcement also increases. It happens because with the increase in pier size pier stiffness increases that reduced the seismic time period and increase the Sa/g value and ultimately the seismic coefficient and seismic forces which causes to increase the pile reinforcement.

7. REFERENCES

Various research papers and literatures are used for technical reference for this study which are listed as below:

1. Patel Nirav, M., & Raval, D. H. Analysis, Design and Economic Implications of Tall Pier Bridge and Foundation.

2. Kimura, M., Inazumi, S., Nishiyama, Y., Tamura, H., Kobayashi, M., & Ochiai, M. (2008). Applicability of H-Jointed Steel Pipe Sheet Pile as Bridge Pier Foundation.

3. Kim, S., Whang, S. W., Kim, S., & Hyung, W. G. (2017). Application of extended end composite pile design in pile foundation work. Proceedings of the Institution of Civil Engineers-Geotechnical Engineering, 170(5), 455-465.

4. Gupto, A. (2015). Goddesses of Kathmandu valley: grace, rage, knowledge. Routledge India.

5. Russo, G. (2018). Analysis and design of pile foundations under vertical load: an overview. Rivista Italiana di Geotecnica, 52(2), 52-71.

6. IRC:6-2017: Standard Specifications and Code of Practice for Road Bridges. Section: II Loads and Load Combinations (Seventh Revision).

7. IRC:112-2020: Code of Practice for Concrete Road Bridges (First Revision).

8. IRC:78-2014: Standard Specifications and Code of Practice for Road Bridges. Section VII Foundation and Substructure (Revised Edition).

9. IS 2911 (Part1/Sec2):2010 Design and Construction of Pile Foundations-Code of Practice. Part 1 Concrete Piles, Section 2 Bored Cast-in-Situ Concrete Piles.

10. IRC:SP:114-2018: Guidelines for Seismic Design of Road Bridges.

11. IRC:SP:105-2018: Explanatory Handbook to IRC:112-2011 Code of Practice for Concrete Road Bridges.

12. IRC:-2015: Standard Specifications and Code of Practice for Road Bridges. Section-I General Features of Design (Eighth Revision).

13. RDSO/B-10427: Road over Bridge, Bow String Steel Girder 60.0m Clear Span for NHAI.

14. IRC:SP:87-2019: Manual of Specifications and Standards for Six Laning of Highways (Second Revision).

15. MORT&H (Fifth Revision): Specifications for Road and Bridge Works.