GEOTECHNICAL INVESTIGATION ACEH ROAD/BRIDGE RECONSTRUCTION & REHABILITATION PATEK BRIDGE LOCATION

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1 GEOTECHICAL IVESTIGATIO ACEH ROAD/BRIDGE RECOSTRUCTIO & REHABILITATIO PATEK BRIDGE LOCATIO Samuardi Batubara Program Studi Teknik Sipil, Univerita Katolik SantoThoma, SU 1. ABSTRAK Thi paper preent the reult of geotechnical invetigation and engineering aement for propoed Patek Bridge at Sta The paper include analyi and deign of deep foundation baed on the oil invetigation data. The deign will be one of the engineering reference to confirm the pile foundation deign of Patek Bridge - Aceh Road Recontruction Project. The purpoe of our invetigation were to explore the oil condition at project area and to provide recommendation in relation to the foundation deign. Key word geotechnical, drilling, foundation, compreion, lateral ITRODUCTIO Thi report preent the reult of geotechnical invetigation and engineering aement for propoed Patek Bridge at Sta The report include analyi and deign of deep foundation baed on the oil invetigation data. The deign will be one of the engineering reference to confirm the pile foundation deign of Patek Bridge - Aceh Road Recontruction Project. 2. SCOPE AD PURPOSES The purpoe of our invetigation were to explore the oil condition at project area and to provide recommendation in relation to the foundation deign. The cope of the invetigation included Drilling, performing tandard penetration tet, taking unditurbed ample and continuou coring. A laboratory teting program on unditurbed ample to evaluate the engineering characteritic of the uburface trata encountered. Performing engineering analyi to evaluate and to provide ite pecific geotechnical information required for deign recommendation.. FIELDWORK AD LABORATORY TESTIG Fieldwork wa carried out from 1 December 2007 until 16 December 2007 and compried the following One borehole ( BH-01), Abutment -1 at coordinate (), (E) drilled to 18.00m with elevation of exiting ground level m. Borehole were advance uing rotary wah bore method and teting wa carried out at 1.50 m interval. Teting compried SPT in non coheive and tiff coheive oil and UD ampling in oft to firm coheive oil. All of the teting wa carried out under the full time uperviion of geotechnical engineer who were reponible for et out, chedulig in hole teting, logging of recorvered ample and election of ample for ubequent laboratory teting. Laboratory teting wa carried out in our Medan laboratory. 4. GEOTECHICAL CODITIO In thi part we explain the reult of ite invetigation at Patek Bridge uch a Drilling and Standard Penetration Tet (SPT). From drilling data at Patek Bridge we can define the elevation of ground water table i about 0.0 m from the exiting of ground level where drilling i done. The ground water condition decribe that oil trength i influenced by the water, which hould be conider during tructure excavation. Detailed report for the drilling are provided in appendix A. The tratification of oil of borehole report indicate very tiff fine andy clay for the upper 1.00 m depth underlain by medium dene medium and mixed hell until 2.00 m depth and underlain by dene clayey and until 6.00 m SEMIAR ASIOAL-1 BMPTTSSI - KoTekS 5 G-125 Univerita Sumatera Utara, Medan - 14 Oktober 2011

2 depth.. to coare and & hell indicated until 8.00 m depth which i underlain by dene clayey and until and underlain by looe fine any clay indicated until m depth. At 4.50 m depth found dene clayey and with -SPT value more than 50 and then until 1.50 m depth -SPT value decend. The very dene tone and napal depth i begun at m with -SPT value more than FOUDATIO SYSTEM The following lit identifie ome of condition that require pile foundation (Veic, 977). 1. When one or more upper layer are highly compreible and to weak to upport the load tranmitted by the upertructure, pile are ued to tranmit the load to underlying bed rock or tronger oil layer. When bedrock i not encountered at a reaonable depth below the ground urface, pile are ued to tranmit the tructural load to oil gradually. The reitance to the applied tructural load i derived mainly from frictional reitance developed by the oil-pile interface. 2. When ubjected to horizontal force. Pile foundation reit by bending, while till upporting the vertical load tranmitted by the upertructure. Thi type of ituation i generally encountered in the deign and contruction of tall tructure that are ubjected to high wind or earthquake force.. In many cae, expanive and collapible oil may preent at the ite of a propoed tructure. Thee oil may extend to a great depth below the ground urface. Expanive oil well and hrink a their moiture content increae and decreae, and preure of the welling can be coniderable. 4. The foundation of ome tructure, uch a tranmiion tower, offhore platform, and baement mat below the water table, are ubjected to uplifting force. Pile are ometime ued for thee foundation to reit the uplifting force. 5. Bridge abutment and pier are uually contructed over pile foundation to avoid the lot of bearing capacity that a hallow foundation might uffer becaue of oil eroion at the ground urface. The axial compreion capacity of driven pile can be calculated by emi empirical method or load tranfer method. In thi cae we apply the load tranfer method to calculate the ultimate axial compreion tet for driven pile with quare 40 x40 cm and diameter 60 cm. Prediction of pile capacity by Standard Penetration Tet (SPT) Prediction of the Bearing Capacity of Pile Baed Excluively on Value of the SPT by Meyerhoff Q p C.. where C ³ 40 ued 40 (1) L C 4. D Q f. A A p Where ; Qp Ap D Q A L Qu f 0.204x ' or (2) '.AS Q () 5 A D.. L 0 1 ' (4) n Q Q Q u p (5) Q u Q a (6) FS = ultimate of end bearing capacity = value of SPT = area piler = Diameter piler = Ultimate of friction capacity = Area of perimeter = of pile = Ultimate bearing capacity G-126 SEMIAR ASIOAL-1 BMPTTSSI - KoTekS 5 Univerita Sumatera Utara, Medan - 14 Oktober 2011

3 Qa = allowable bearing capacity C = Soil coefficient K = Soil coefficient F = Skin fractional tre = Average SPT FS = Safety factor = 2.5 With C = oil coefficient Soil Type C (t/m 2 ) Clay 12 Clayey Silt 20 Sandy clay 25 Sand 40 Allowable axial compreion capacity of pile baed SPT Value can be een in Table 1 and 2. Table 1. Allowable axial compreion capacity of pile quare 40x40 cm baed SPT Value BH-01 Square 40x40 cm (m) ' AS Ap Qp Q Qu Qa (SQ=0.4) (SQ=0.4) (ton) (ton) (ton) (ton) Table 2. Allowable axial compreion capacity of pile D = 60 cm baed SPT Value BH-01 D=0.6m (m) ' AS Ap Qp Q Qu Qa (d=0.60) (D=0.60) (ton) (ton) (ton) (ton) egative kin friction on pile Due to the ite fill over the exiting oft oil at the plan ite, we recommended to include the negative kin friction in calculating the allowable compreive bearing capacity. The unit negative kin friction i calculated a uggeted by Bjerrum (1965) uing the following equation For coheive oil f 0.20 p 0 (7) SEMIAR ASIOAL-1 BMPTTSSI - KoTekS 5 G-127 Univerita Sumatera Utara, Medan - 14 Oktober 2011

4 For coheionle oil 1 f. k. p 0.tan( ) 2 4 (8) Where f = unit negative kin friction p 0 = effective overburder preure k = coefficient of lateral earth preure = internal friction angle of coheionle The ultimate negative kin friction then to be calculated by uing the following equation Where P D L f Laterally loaded pile = ultimate negative kin friction on pile = diameter of pile = length of pile to neutral point = unit negative kin friction P. D. L. f (9) Analyi of the lateral capacity of pile in coheionle oil baed Brom Method (1964). The laterally loaded pile i calculated a uggeted by Brom for long pile uing the following equation y o 0.9H / 5 2 / 5 n h.( E I ) (10) Where y o deflection H lateral load n h relative denity E modulu of elaticity I moment of inertia The value of the coefficient of modulu variation n h can be een in Table. 6. Table. Factor for calculating coefficient of modulu variation (n h ) for coheionle oil Relative denity Looe dene Dene n h for dry or moit oil (Terzaghi) (k/m ) n h for ubmerged oil (Terzaghi) (k/m ) n h for ubmerged oil (Reee et al) (k/m ) COCLUSIO/ RECOMMEDATIO From the geotechnical invetigation and analyi we can conclude 1. The ground water level at ite i about 0.0 m from the ground urface. Thi information i important during tructure excavation and for calculation the effective overburden tre of oil. 2. At 4.50 m depth i found very dene clayey and and -SPT value more than 50. At thi level continuing driving might be damage to the pile cap, o when thi level will be conidered a bearing trata then the capacity of lateral and lift up hall be conidered.. Soil tratification at m depth i fine andy clay, medium and mixed hell, clayey and, medium to coare and mixed hell, clayey and, fine andy clay and tone. The very dene tone and napal layer tart at depth m with -SPT value more than 50. When neceary and deal with the condition of the contract, in order to reach the driving pile until m depth, pre-boring hould be conidered to penetrate at the 4.50 m depth. REFERECE Annual Book of ASTM Standard 1989 Volume Bowle,J.E., Engineering Propertie of Soil and Their Meaurement, Mc Graw Hill Book Company. Da, B.M., Principle of Geotechnical Engineering PWS Publihing Company, Boton Da, B.M., Principle of Foundation Engineering, Thomon, Book Hunt, R.E., Geotechnical Engineering Technique and Practice, Mc Graw Hill Book Company. M.J. Tomlinon Pile Deign and Contruction Practice A Viewpoint Publication G-128 SEMIAR ASIOAL-1 BMPTTSSI - KoTekS 5 Univerita Sumatera Utara, Medan - 14 Oktober 2011

5 = = Geoteknik APPEDIX A BOREHOLE & SPT REPORT Bridge ame PATEK Bore Location Abutment - 1 ACEH ROAD/BRIDGE RECOSTRUCTIO AD REHABILITATIO PROJECT BORE LOG Standard Penetration Tet (SPT) Symbol Type of Tet (m) Station () (E) Coordinate M Elevation December 1-16, 2007 Date Ground Water Level -0.0 M o. of Blow of Layer Value 45 cm SPT Platicity Platicity Platicity Platicity Platicity Platicity Platicity ED OF BORIG Fine Sandy clay Darkly brown Very tiff Low m and mixed hell Redly yellow dene on platic m Clayey and Dene on platic m to Coare and & hell Dene on platic Low m Clayey and Dene on platic m Fine andy clay Yellowih grey Looe m Stone & napal Very dene on platic Low m /2 > /12 >60 60/12 > COHESIVE SOIL*) Legend Standard Penetration Tet (SPT) Unditurbed Sample (US) Diturbed Sample (DS) Sandy Clay - -Value GRAULAR SOIL*) -Value Denity Sand - Very Soft Very Looe Clayey Fine Sand - Soft Looe to Coare Sand Soft Clay Stone/Rock/Coral Very Stiff Hard Very Hard - > ROCK QUALITY DESIGATIO (ROD) *) - R 20% Very Poor - <25 Poor Dene Fair Dene Good Stiff Ground Water Level (GWL) *) LEGEDS SYMBOLS AD RAGE OF VALUE >50 -Very Excellent - >90 Dene reference from handbook of Joeph E. Bowle, Foundation Analyi and Deign; fourth edition. Page 141 SEMIAR ASIOAL-1 BMPTTSSI - KoTekS 5 Univerita Sumatera Utara, Medan - 14 Oktober 2011 G-129

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